Boris Johnson has insisted disgraced MP Rob Roberts received an appropriate punishment for breaching sexual misconduct rules.
Mr Roberts, who represents Delyn, faces being suspended from the Commons for six weeks after he made repeated unwanted advances to a member of staff.
He has been stripped of the Tory whip but the way recall laws are drawn up means he cannot face the prospect of losing his seat.
The sanction was proposed by the panel set up in 2020 to deal with cases raised under the Independent Complaints and Grievance Scheme.
But the Recall of Parliament Act was passed in 2015 and only allows the prospect of a by-election for sanctions imposed on the recommendation of the Commons Committee on Standards.
Prime Minister Mr Johnson was challenged by Labour MP Gerald Jones to introduce emergency measures to close the loophole within the existing rules, something the Government had earlier pledged to do.
Mr Johnson told Mr Jones he would “take that point very seriously” before adding in the Commons: “If he is referring to a Conservative member who has recently had the whip taken away, he can take it that that member has already had condign punishment.”
At this stage, one Labour MP could be heard shouting “six weeks”, a nod to the punishment recommended for Mr Roberts.
Cabinet minister Grant Shapps earlier said the loophole in Mr Roberts’ case needed to be closed.
The Transport Secretary told BBC Radio 4’s Today programme: “This has gone through a new independent process and doesn’t have the same rules about the so-called recall process which is where constituents can essentially call for an election.
“Although it’s a decision for the House of Commons, I rather agree that this loophole does need to be closed.”
Commons Leader Jacob Rees-Mogg “will be saying more about the lack of recall provision”, he added.
“This should not have the exemption from recall just because it has gone through this newly independent process and I know the Leader of the House intends to come forward and say more about it.”
Mr Rees-Mogg will invite the “relevant bodies” to consider whether the laws need to be changed to enable the recall process to be triggered.
A Government spokesman said: “A case of this severity highlights the need to look again at whether the process is striking the right balance between protecting the confidentiality of complainants and ensuring consistency with other types of conduct cases.
“The central aim of the Independent Complaints and Grievance Scheme is to help improve the working culture of Parliament and it will need to continue to evolve and improve over time.
“The Leader of the House will invite the relevant bodies to consider whether any changes could be made in future to the process to enable recall to be triggered.”
MPs need to approve the six-week suspension.
Had a suspension of a fortnight, or 10 working days, been imposed on the recommendation of the Commons Committee on Standards the threshold for a recall petition would have been met.
Once a petition is open if 10% of eligible voters in a constituency sign it then a by-election is triggered.
Labour MP Chris Bryant, chairman of the Committee on Standards, said it was a “glaring anomaly” that the recall process was not triggered by a sanction recommended by the Independent Expert Panel.
The Prime Minister’s official spokesman said: “This is fundamentally a decision for the House of Commons, but a case of this severity has raised questions around whether changes need to be made in order for a recall to be triggered in the future.
“So the Leader of the House of Commons is going to be having conversations across the House over the next few days urging them to consider what more can be done to improve the system.”