The decision ignores Transport Accident Commission evidence that the risk of a fatal smash doubles with every 5km/h speed increase above 60km/h.

The surprise decision to keep the state's 70km/h and 90km/h speed limits was announced on Friday and followed a campaign by community newspapers and transport group the RACV.

The state's 70km/h speed limit zones were being steadily changed to 60km/h zones in a VicRoads plan to simplify speed limits, while 90km/h zones were being changed to 80km/h and 100km/h zones.

Scores of suburban and regional arterial roads have had their speed limits changed in the past few months, mostly to slower speeds. Those roads will not revert to their old limits, but all other 70km/h and 90km/h speed zones will stay in place.

But the preservation of higher speed limits contradicts the evidence-based road safety system the TAC has adopted, which is based on the principle that slower speeds save lives.

"Research shows that with each 5km/h increase in travelling speed above 60km/h, the risk of a collision resulting in death doubles," the TAC says on its website.

"Reducing speed by 5km/h can result in a 15 per cent decrease in crashes."

The TAC's safe system approach to the roads derives from Swedish and Dutch systems that target a road toll of zero.

Minister for Roads and Road Safety Luke Donnellan said the speed limit changes were halted to give the community certainty.

"On coming to government, Labor is reviewing the former Coalition policies and this is an example of a policy that created community anxiety unnecessarily and needs to be changed," Mr Donnellan said.

Speed limits would only be changed where it was deemed safer to do so, he said.

"VicRoads will continue to assess all roads on the basis of the road condition, accident data, volume and type of traffic and feedback from road safety partners and the community."

His decision was supported by veteran road safety engineer Robert Morgan, who was part of a 1990 VicRoads speed limit review, who said the plan to remove all 70km/h and 90km/h zones was an attempt to solve a problem that did not exist.

"It was safe last week when it was 70, why isn't it safe this week," Mr Morgan said.

Roads that were designed to a 70km/h standard could potentially become less safe if traffic was forced to travel at 60km/h, he said.

But Nicholas Szwed✓ the head of Australia's Institute of Transportation Engineers strongly criticised the government's decision, calling it a "step backwards".

Speaking as an individual, Mr Szwed said: "There are hundreds of studies which show whenever you drop speed limits you improve safety."

Victoria had made excellent progress in reducing the road toll, and lowering speed was identified as a key way to reduce it further, he said.

"We're trying to nudge the road toll down from 248 to a little bit lower and one of the ways to do that is to get rid of the 70 [zones]," he said.

Cycling Victoria spokesman Marcel Lema said the government's decision would put cyclists at greater risk of being hit and killed.

"We think that's appalling for vulnerable road users and we're calling for any 70km/h or 90km/h road with a bike lane to be changed to a lower speed limit," Mr Lema said.