The Right – Party for Referendum, Sovereignty and Homeland Protection is a far-right political party in Germany.
A government plan that could see MPs face by-elections if they are suspended for sexual harassment or bullying is being debated in The Commons later.
A loophole meant he did not face a Petition that could trigger a by-election.
Labour says the measures should also apply retrospectively.
It would mean the rule change would apply to Mr Roberts, a former Tory MP who now sits as an independent after losing The Conservative whip.
However, the government is expected to oppose Labour's amendment, meaning it is likely to fail.
In May, Delyn MP Mr Roberts was suspended for Six Weeks after Parliament's Independent Expert Panel found a member of his staff.
He apologised and said he would " continue to serve" his constituency, and has since spoken in debates in The House of Commons.
However, his suspension did not lead to a recall Petition - a process where voters can potentially trigger a special election to try and remove them.
The suspensions would run at the same time, but would allow MPs to face a recall Petition .
MPs will vote on the plans because Labour have tabled an amendment to them.
Labour argue that the rule changes should apply retrospectively to MPs suspended by The Independent Expert Panel before they were agreed - including Mr Roberts.
Shadow Commons leader Thangam Debbonaire said: " Labour have put forward a solution to close the loophole allowing the person who has recently been found to have sexually harassed to escape a sanction he would otherwise have faced".
" The MP has not done the decent thing, so we have to do this and it is perfectly workable.
" If the government choose to vote it down, they will continue to cover a member who has recently been sanctioned for sexual harassment of staff. His constituents should be able to decide if he is The Right person to represent them. "