Andrew Mitchell, the Conservative government's former chief whip in the House of Commons, said if Evans steps down amid allegations he's denied, all lawmakers will be called upon to resign whenever allegations are made, The Daily Telegraph said Monday.
Two men in their 20s came forward last week and accused Evans, 55, of rape and sexual assault. Police investigated the claim, interviewed Evans and searched his home. He has not been charged though the investigation is ongoing.
Evans came out in 2010 after he said political opponents threatened to use his sexuality against him.
He said he regarded two men who accused him of the crimes as friends -- and had socialized with them as recently as a week prior to the allegations being made.
Evans is the House of Commons deputy speaker.
Mitchell quit the parliament leadership position last year after allegations he swore at police officers during a dispute, calling them "plebs."
Mitchell said he'd known Evans for years and thinks the allegations aren't true.
"I simply do not believe these allegations that have been made against him," he said.