The Clwyd South Labour MP won cross-party support to introduce a bill to Parliament that sought to review sentencing for unlicensed or uninsured drivers who kill or seriously injure people.
Susan Elan Jones MP said: "Far too many people have been injured and killed on our roads for us to give up the fight for road safety. From the community in Overton who campaigned for and got a 40 mph buffer zone to communities both sides of the border who are campaigning for a dual carriage on the A483/A5, road safety is a big issue in our area.
"We must continue with our campaigning and we must all work together cross-party. However we really can't do this when speeding is trivialised. I really hope that Conservative candidates in this election will make it quite clear that they do not support a 80 mph speed limit on any road. It is a very bad idea."
Brake spokesman Jack Kushner said: "We urge the government to reject needless proposals to increase speed limits to 80mph.
"We're disappointed it is being considered. Evidence from previous consultations made it clear that an increase would not only be dangerous - potentially 25 more deaths and 100 more serious injuries each year - but also highly damaging to the environment and economy."