Key crossbench Senator Ricky Muir has issued a fresh challenge to Education Minister Christopher Pyne, urging him to seek an election mandate on the government's university reforms.

Senator Muir's position casts further doubt on whether Mr Pyne can successfully convince at least two crossbench senators who voted against the controversial reforms at the end of 2014 to change their minds and back the package in 2015.

Senator Ricky Muir has issued a fresh challenge to Education Minister Christopher Pyne. Credit:Alex Ellinghausen

The Australian Motoring Enthusiast Party senator's view are roughly in line with independent Senator Nick Xenophon, who has called for a review of the higher education sector and delay to any major reforms until after the next federal election.

Prime Minister Tony Abbott's office called Senator Muir on Tuesday to open talks for the new year. Senator Muir said that while he was listening and consulting on proposals to reform the higher education system he still holds concerns about the prospect of soaring fees should they remain uncapped.