Public Transport and Roads Minister Terry Mulder has hosed down hopes that the speed limit on the Princes Highway would be raised to 110km/h after reports the government was secretly planning to do so.

Speaking to radio station 3AW on Monday, Mr Mulder said "at this point in time, I certainly have not approached the Assistant Commissioner or the Commissioner and asked them to support this".

"There's nothing wrong with discussing the issue ... [but] if we were to do that today, the crash rate along that road would go up around 30 per cent, fatalities would go up, injuries would go up," Mr Mulder said.

The minister added that while he was not ruling out an increase in the future, the road in its current state could not support the change.

"There are potential major upgrades to the road that could bring the speed limit up ... but to change the speed zone signs on that road [today] would result in a catastrophic impact in relation to road safety."