The Government will give police new powers to conduct random roadside drug testing, and to prosecute drugged drivers in a bid to save lives on the road.

"The new powers will send a clear message that if you take drugs and drive, you will be caught," Associate Transport Minister Julie Anne Genter said.

Last year, 95 people were killed in preventable crashes where the driver was found to have drugs in their system.

The new rules – which will go through Parliament next year – mean the police will be able to conduct oral fluid drug testing on drivers.

Genter expects it come into force in early 2021.

Any drivers who test positive for the presence of drugs will be fined and immediately suspended from driving for a minimum of 12 hours.

Drivers will also face criminal penalties if they fail a compulsory impairment test and blood tests confirm impairing levels of drugs in their system.

"The change will allow police to test drivers for the presence of drugs and impairing medication anywhere, anytime, just as they can for alcohol," Genter said.

The Drug Foundation's executive director Ross Bell welcomed the Government's move.

He said it represents a change in heart for not just the Government, but also for New Zealand.

"We know drug driving is an issue and we know police need to be equipped with the right tools.

"But the Government has been a bit nervous about rolling out [these tests] because they are not without their issues."

He said there had been some issues in the past with tests producing a false positive reading.

But he said it was likely technology would develop in the future which would help mitigate this issue.

Genter, however, said the Government has a plan to tackle the false positive issue.

"The way we have designed this means it does have some practical and pragmatic fail-safes to ensure that we're not getting false positives."

That means if someone fails one test, they will be given another one – if they fail that, "you will face penalties".

The new rules will comes as welcome news to the National Party, which have been campaigning for such a test for much of this year.

Leader Simon Bridges has complained that it has taken so long for the Government to move on this issue.

"National wants a proper roadside drug testing regime in place as soon as possible and before any of the Government's law changes liberalising access to drugs takes effect," he said in a May press release.

But Genter said the legislation had not been delayed – "we have progressed this as fast as we possibly could [have]".

She said she would be surprised if National did not support this when it comes before the House.

She said this was just one part of a very broad work safety programme, which she will be making more announcements about tomorrow.