Labour is to stage a Commons vote on banning MPs from taking paid consultancies or directorships, Sir Keir Starmer said.
The Labour leader said the party will be tabling a motion for Wednesday’s opposition day debate.
It is understood Labour is seeking to draft the motion in such a way that the result will be binding on the House if it is passed.
Sir Keir said it offered a way to “clean up” politics following the debacle of the case of former Cabinet minister Owen Paterson.
“We are putting that down. It is for every MP to decide how they want to vote on that. That will perhaps be a measure of where people are on how we actually move this forward,” Sir Keir said during an LBC radio phone-in.
“How do we clean this up? We clean this up by drawing a very stark line – no paid consultancies, no directorships.”
The move comes as MPs are expected to back a motion reversing plans to review the MPs standards investigation process and delay Mr Paterson’s suspension for breaking lobbying rules.
Many Tory MPs are still furious after being ordered to support the review only for the Government to drop the plan after the opposition parties refused to back it.
Mr Paterson, meanwhile, has resigned as the MP for North Shropshire.
The House, however, is still expected to endorse the finding that he broke Commons rules by repeatedly lobbying ministers and officials on behalf of two firms which he worked for as a paid consultant.
In a second motion, Labour will call for the publication of the papers relating to his advocacy for the diagnostics company, Randox, and all the Government contracts it received.
At a Downing Street news conference on Sunday, Boris Johnson acknowledged he could have handled the situation better.
“Of course, I think things could certainly have been handled better, let me put it that way, by me,” he said.
During a round of broadcast interviews on Monday, Conservative Party chairman Oliver Dowden acknowledged it had been a “mistake” for ministers to “conflate” Mr Paterson’s case with attempts to reform the standards procedures.
“The Prime Minister has accepted – and we accept – that there were mistakes made during that period,” he told BBC Breakfast.
“If you listen to what the Prime Minister said, he said that we’ve made mistakes and we regret that. We’ve accepted that, we’re moving on.”
Mr Johnson refused to be drawn on the issue during a visit on Monday to a medical centre in Forest Gate in east London.
Speaking during a pooled broadcast clip, the Prime Minister said: “I just want to salute you and the media for keeping going on this.
“I’m here to talk about boosters and urge people to come forward and get their boosters.”
Asked about reports that Transport Secretary Grant Shapps set up a group to lobby against housebuilding on airfields, Mr Johnson said: “If there are things to be investigated, then of course, that should take place.”
Labour’s decision to force a vote will put pressure on Tory MPs who face the prospect of further stoking public anger by seeking to vote it down or losing their lucrative consultancy work.
An analysis published by the party last week showed Conservative MPs received more than £1.7 million in consultancy fees since the start of the year.
It found 50 Tory backbenchers and former ministers had been paid by management or consultancy firms.
Sir Keir said: “It should be a point of consensus that paid directorships and commercial consultancies are not jobs for MPs.
“It was the Prime Minister’s decisions which have led to this scandal. He has repeatedly failed in his leadership over this issue.
“Boris Johnson now has a choice: support Labour’s plan to fix this or whip his MPs to vote against a ban on dodgy second jobs for MPs and a cover-up on the Owen Paterson scandal.”