Transport Minister Simeon Brown hasn't yet received advice on how many more deaths from changing speed limit rules

The Transport Minister says he hasn't yet received advice on how many more deaths could be caused by the Government's move to put the brakes on blanket speed limit reductions.

And Simeon Brown told AM he's also yet to be advised on what productivity gains could be made from removing the blanket requirement to review speed safety on all roads, which the minister announced on Tuesday would be going ahead.

First, Brown would have to rewrite the rule to take those factors into account, he said.

"That's where I'll be receiving that advice," Brown told AM host Ryan Bridge.

Reversing speed limit reductions on state highways and neighbourhood streets, at an estimated $30 million cost, was one of National's election promises. That's despite the former Government in March already significantly watering down blanket speed limit reductions, with then-Prime Minister Chris Hipkins in March announcing changes would only be made to the most dangerous 1 percent of state highways - with targeted drops to areas near schools, marae and some small towns.  

Brown said, however, the previous Government's road safety budget was "being used to slow people down".

"There was a whole lot of money being put into a whole lot of those areas which effectively just make it inconvenient to get around our cities and our regions - we're going to take a much more balanced approach. People need to get where they need to go quickly and safely, we need to be able to travel efficiently and so we will be taking an approach that says, 'Actually, movement of people and goods is really, really important.'"

Simeon Brown.
Simeon Brown. Photo credit: Newshub.

Brown was also asked by AM how much money the Government would save by scrapping the blanket speed reduction rule.

The Government was currently rewriting its transport policy statement, Brown said. That statement would "go into all that detail" around savings, he added.

Hipkins, now the Opposition leader, told AM on Wednesday it was "possible we'll end up with more people being injured or more people dying on our roads".

"Having said that, Waka Kotahi make these decisions independently - the speed limits get set by them and I'm sure they'll continue to do that independently," the Labour leader said.

"Their numbers didn't add up before the election and they're getting worse after the election, as they realise a lot of the things that they promised people where they said they were going to save money... actually all do cost money," Hipkins said of the National-led Government.

According to the World Health Organization, an increase in an average speed of 1km/h can result in a 3 percent higher risk of a crash and a 4-5 percent increase in fatalities.