Ex-Welsh Secretary Stephen Crabb says Truss has weeks to prove herself
A senior Welsh Tory backbencher says the next few weeks will show Liz Truss will lead the party into the next election.
Stephen Crabb, who was Welsh Secretary until 2016, said Liz Truss should be given "some space" to provide "consistent, purposeful leadership".
But the Preseli Pembrokeshire MP said it had been a "dreadful start to her time in office".
His comments came before the home secretary resigned.
Grant Shapps has replaced Suella Braverman, who quit after sending an official document using her personal email.
Speaking to BBC Wales, Mr Crabb did not echo comments by Bridgend Tory MP Jamie Wallis calling for Liz Truss to go.
He said he had not written to Sir Graham Brady asking for the Tory leader to quit.
Mr Crabb said: "I think the prime minister does need to be given some space to try and lead her government at this point in time.
"It's been a pretty dreadful start for her time in office."
But the MP said that given where the markets are "I don't think adding further political instability at this time will help that at all".
"She needs to be able to show she can run the government in a very clear and purposeful way, not like what we've seen in recent weeks where policies seem to be up in the air and changing from day to day".
The "next few weeks will be crucial," he said.
Asked if he could see her being the leader that takes the Conservatives into a general election, he added: "I have no idea - if she says she wants to lead us into the next election, well let's see how the next few weeks go."
In her letter of resignation, Ms Braverman acknowledged this was a "technical infringement" of rules.
She said people should accept responsibility for mistakes and added - in what will be seen as criticism of the PM - "pretending we haven't made mistakes... is not serious politics.