Alcohol and drug limits

Alcohol and drugs, including some drugs given to you by a doctor, can seriously affect your driving. They can slow your reaction times and affect your senses.

You risk causing death and serious injury to yourself and other people if you drive under the influence of alcohol or drugs.

The impact of alcohol on driving safely

The impact of drugs and medication on driving safely

Road to zero - where everyone can get to where they're going safely

Legal alcohol limits for driving

The law says you must not drive if the amount of alcohol in your blood or breath exceeds certain age-related limits. 

Under twenty

There's a zero alcohol limit if you're under 20. That means if you drive after consuming even one drink you can be charged with drink-driving.

• If you have an alcohol level of less than 150 micrograms per litre of breath, or less than 30 milligrams per 100 millilitres of blood, you could be fined and given 50 demerit points.
• If your alcohol level is higher, you could be disqualified from driving, given 50 demerit points and either fined or imprisoned.

Twenty or over

You must not drive if you have more than 250 micrograms of alcohol per litre of breath, or more than 50 milligrams of alcohol per 100 millilitres of blood.

• If you have an alcohol level between 251 and 400 micrograms per litre of breath, or between 51 and 80 milligrams per 100 millilitres of blood, you could be fined and given 50 demerit points.
• If your alcohol level is higher, you could be disqualified from driving and either fined or imprisoned.

Penalties for drink-driving

Indefinite disqualifications or alcohol interlocks for repeat offences

It's difficult to say how many alcoholic drinks you can have before you reach these limits. It depends on many things, including:

• your gender
• your size
• how much food you've eaten.

Because even small amounts of alcohol can affect your driving, the best advice is: if you drink at all, don’t drive.

Drugs and driving

The law also says you must not drive if you've taken any type of drug that may affect your driving ability.

From 11 March 2023, there are new offences and penalties if you take any of 25 specific drugs above the legal limit for driving. 

These drugs could be ingredients in a range of prescription medications or illegal drug products. 

If you are prescribed medication, you need to understand and follow the instructions given to you by your doctor, pharmacist or the manufacturer of the medication.  

If you're unsure whether your medication may affect your ability to drive, or if you're experiencing any side-effects, the best advice is: don't drive.

List of 25 drugs covered by the new law(external link)

Medication and illegal drugs

Penalties for drug-driving

Testing for alcohol and drugs

You can be stopped by the police and tested at any time for alcohol and drugs. The police can use the following tests to see if you've been drinking or taking drugs.

Passive breath test

The police officer will place a hand-held device in front of your mouth and ask you to talk into it. This will show if you have recently drunk any alcohol. If any alcohol is detected, a breath screening test will be required

Breath screening test

The police officer will give you a small electronic device, and will ask you to blow into it. If your alcohol level is high, you'll be asked to take an evidential breath test or have a blood test.

Evidential breath test

This is an electronic device you blow into, which gives a reading that can be used in court as evidence of your breath–alcohol concentration.

Blood test

If you have a blood test, a medical doctor or other approved person will take a sample of your blood to be tested for alcohol or drugs.

Compulsory (drug) impairment test

This includes an eye assessment, a walk and turn, and a one leg stand assessment. If you fail you may be forbidden to drive and required to have a blood test.

When are the tests carried out?

A police officer can ask you to take a passive breath test or breath screening test if:

• you're suspected of drinking and driving
• you're signalled to stop at a police alcohol check point.

You must wait with the officer for the result of the test.

If the test shows you've been drinking, you must:

• take a further test – this will be either an evidential breath test or a blood test
• hand over the keys to your vehicle, if asked by a police officer
• go with a police officer, if required
• agree to a blood test, if asked by a police officer, medical doctor or other approved person.

If you don’t, you may be arrested.

A compulsory impairment test can be required if a police officer has good cause to suspect you're impaired by drugs. This could be because of your erratic driving, or if you've been stopped for another reason and appear to be under the influence of drugs.

What are your rights?

You may:

• choose not to take a breath screening or evidential breath test – however, if you:
  • refuse a breath screening test, you'll be asked to take an evidential breath test
  • refuse an evidential breath test, you must undergo a blood test
• choose to have a blood test, if an evidential breath test shows you're over the legal limit. The court will take the results of the blood test over the results of the evidential breath test
• talk to a lawyer (if you wish to) after a positive breath screening test and before an evidential breath or blood test – a phone will be made available to you for this purpose.

If your blood test shows you're over the legal limit, you'll be given a copy of the blood test certificate.

You may ask for your blood sample to be tested by an independent analyst. If you want this to happen, it’s important that you talk to a lawyer as soon as possible.

Court-imposed penalties for alcohol/drugs offences

 These tables show some of the penalties for driving offences relating to alcohol and drugs.

Penalties for drug impaired driving or driving with class A or specified drugs in the blood stream

On-the-spot licence suspension

Your licence will be suspended at the roadside if you refuse to have a blood test, or if you're found to have a certain amount of alcohol in an evidential breath or blood test. 

Roadside licence suspension

Repeat offences

The penalties described above may be increased substantially for repeat offences.

If you commit 2 alcohol-related offences within a 5-year period and one of those offences involves:

• refusing to go with a police officer
• refusing to give a breath or blood sample
• driving under the influence of alcohol or drugs
• having a breath–alcohol level above 1000 micrograms
• having a blood–alcohol level above 200 milligrams per 100 millilitres

then you'll be:

• disqualified from driving for an indefinite period, and
• required to attend a Ministry of Health alcohol assessment centre.

Indefinite disqualifications

If you commit an alcohol-related offence and:

• your breath and/or blood alcohol levels are twice the legal limit or higher, or
• you've already been convicted of a previous offence (as listed above) within a 5-year period

then you could be:

• given an alcohol interlock disqualification with an accompanying three-month disqualification period, or
• given a zero alcohol disqualification.

Alcohol interlock programme

Zero alcohol licences

More information

Download Factsheet 55: Driving offences and penalties [PDF, 261 KB]