Fairfax Media reported in April that 660 officers had incorrectly been given authorisation to test drivers because of an administrative error.

Mr Noonan, in his second reading speech for the Victoria Police Amendment (Validation) Bill, revealed that the error had affected more than 1400 tests.

That is about 13 per cent of all drug and alcohol tests performed in Victoria between July 1 last year and March 5, when the error was detected.

He said the retrospective legislation was a matter of last resort but had to be introduced as there was "a risk that legitimate prosecutions and infringements for drink and drug driving that rely on evidence obtained through these tests could fail on a technicality."

More than 1100 drivers were issued penalty notices or charged with criminal offences after being tested by an officer unauthorised to carry out the tests.

Preliminary road-side breath or saliva tests, which are not required to be conducted by an authorised officer, were not affected.

"Urgent legislation is required to mitigate the risk that enforcement actions conducted in reliance on evidence obtained by an officer operating under an invalid authorisation is adversely affected," Mr Noonan said.

"I am of the firm view that this retrospective bill is reasonably justified and does not result in unfairness to accused persons in affected criminal proceedings.

"The error is of an administrative nature only and does not affect the accuracy of the tests and assessments performed by the officers, nor the cogency of the evidence relied on in enforcement actions."

Victoria Police identified the error after an internal audit.

The audit found that "certificates of authority" granted to police to operate breath analysing instruments, conduct oral fluid tests and drug impairment assessments were wrongly signed by a deputy commissioner of police.

Instead, the authorisations should only have been issued by the chief commissioner.

It was overlooked that when the Victoria Police Act replaced the Police Regulations Act in July last year, a deputy commissioner could no longer authorise the certificates.

Mr Noonan said it was unlikely an error of this nature would happen again.

The retrospective legislation means that any court or administrative order made, warrant issued, penalty imposed, demerit points incurred, licence suspension or cancellation, property seized or arrest made in "direct or indirect reliance on evidence obtained pursuant to the error will continue to stand."

Victoria's top traffic cop said last month that he backed the integrity of the state's road policing regime, despite two major errors that had thrown doubt over penalties handed to hundreds of drunk or drugged drivers.

In February, Assistant Commissioner Robert Hill admitted that 508 people caught drink driving since 2007 did not have their licence cancelled when they should have, and 195 drivers had been banned from driving when they should have only been penalised 10 demerit points and fined.

The first drink-driving issue, which was unrelated to the error regarding authorisation, could result in dozens of drivers making claims for thousands of dollars in compensation because of potential loss of income and the cost of attending drink-driving courses.

"These are unrelated issues. They were both detected by separate internal reviews initiated by Victoria Police," Mr Hill said in April.

"I'm very confident with the integrity of our road policing operations, and the community can be confident too."