Several prominent Welsh Labour politicians have urged the party's UK leader to table a vote of no confidence in Theresa May's government.
It follows the decision to defer a vote on Brexit on Monday.
MPs Chris Bryant and Owen Smith are among the 40 signatories to the letter to Jeremy Corbyn - along with Labour peer Lord Hain.
It comes as opposition leaders accused Mrs May of showing contempt for Parliament.
The Conservative leader is meeting European leaders and EU officials throughout Tuesday for talks aimed at rescuing her Brexit deal.
Mr Corbyn joined Plaid Cymru's Liz Saville Roberts, Liberal Democrat leader Vince Cable, the SNP's Ian Blackford and co-leader of the Greens Caroline Lucas to sign a letter demanding assurances from the prime minister on what happens next.
The correspondence stated: "We believe that this deferral shows a contempt for Parliament.
"It cannot be right that the Government can unilaterally alter the arrangements, once this House has agreed on a timetable, without the House being given the opportunity to express its will."
Labour was granted an emergency debate on Tuesday on the issue after claiming MPs had been "disregarded".
But the party rejected calls to table a vote of no confidence in Mrs May, with Labour officials arguing it had more chance of success when the Brexit deal came back before MPs.
However, some Welsh Labour politicians have urged Mr Corbyn to act.
MPs Tonia Antoniazzi, Susan Elan Jones, Madeleine Moon, Geraint Davies, Chris Bryant and Owen Smith have all signed a letter to the Labour leadership from Ian Murray asking for a no confidence vote, followed by another referendum.
They have been joined by MEP Derek Vaughan and Lord Hain.
The Aberavon MP Stephen Kinnock has also called for an immediate no confidence vote.
He said it was "the duty of the opposition" to move against a government that has "lost its authority".
In the Commons, Torfaen MP and shadow solicitor general Nick Thomas-Symonds said Mrs May's decision to postpone the Brexit vote was made "in a panicked haste without thinking through the economic, political and constitutional implications for our country".
The Labour MP said: "The prime minister's official spokesperson has reiterated today that the government will bring back the meaningful vote by the 21st of January...
"Isn't it completely contrary to the national interest for the prime minister to run down another six weeks on the clock - when all she is seeking is reassurances and clarification on a document Parliament already understands?"
Earlier, Ogmore MP Chris Elmore called the delay to the vote "ridiculous".
"We're in utterly unprecedented times, where a government is trying to stop its own business because it can't win a vote," he told BBC Radio Wales.
"We are where we are because of the prime minister's stubbornness and her stubbornness is the greatest risk to our country."
Plaid Cymru's leader in the Commons, Liz Saville Roberts has urged Jeremy Corbyn to "just get on with it".
"Bring on the no confidence motion, because something needs to break us from this impasse in which we stand now," she said.