Conservative Liberal MP Tony Pasin says Christopher Pyne's post-politics role at EY "doesn't meet the pub test" and is in breach of lobbying standards, as support for an inquiry into ministerial code of conduct grows.

The criticism comes one day before the Senate is due to debate a bill from crossbench senator Rex Patrick that could see Mr Pyne brought before an inquiry that would examine whether the non-enforceable ministerial code of conduct is operating effectively.

Former ministers Christopher Pyne and Julie Bishop are both facing questions about their post-political jobs. Credit:Andrew Meares

"It's disappointing that [Mr Pyne's EY role] doesn't meet the pub test - and it doesn't - but perhaps it's something we need to reflect on," Mr Pasin said.

But the South Australian Liberal, who has clashed with fellow MP Christopher Pyne in the past, said an inquiry was not the answer.