According to the leader of the party's Senedd, Boris Johnson's support from Tory MPs appears increasingly "tenuous".
Andrew RT Davies stated that it was "debatable” whether the prime minister could still win the support of a majority in Westminster Conservatives.
If so, Mr Davies stated that a change in the prime minister's office was "inevitable".
Boris Johnson, Prime Minister's Questions, stated that he had a "colossal mandate", which he would "keep going" with in his office after the 2019 election.
The Tory Senedd leader, who was a strong supporter for Mr Johnson in the past, would not answer directly if he supports the prime minster.
After two of his top ministers attacked him and his leadership, the prime minister is trying to retain his job.
Within 10 minutes, Chancellor Rishi Shahak and Health Secretary Sajid Javid both resigned. They were followed by junior ministers or aides.
Virginia Crosbie was one of them, and she was the first Welsh MP who called for Johnson's resignation.
The Ynys mon MP, a Parliamentary Secretary at the Wales Office, stated that the prime minister's position was "untenable".
This follows the appointment of Chris Pincher as deputy chief whip by Mr Johnson earlier in the year, despite knowing about misconduct allegations against him.
Andrew RT Davies, speaking on BBC Walescast podcast, said that Downing Street has caused much of the damage.
Mr Davies stated that it was really difficult. It's impossible to underestimate what happened over the past 24 hours.
"But I believe that if a prime Minister and a party win a mandate in a general election that mandate is for full-term. It is for the party leader and the party to go into the next general elections promoting what they've done in government, and what we'd do to get another mandate from the country.
"But, if the prime minister can't command the confidence from the majority of Parliament then that individual's time is over.
He said, "That's what Boris Johnson now must prove in the House of Commons. I think that's disputable."
Plaid Cymru leader Liz Saville Roberts, Plaid Cymru Westminster leader, accused Mr Johnson of prioritizing "political survival" over "public duty" during Prime Minister's Questions.
She said that whatever happens, "the same Westminster arrogance" will continue to determine our futures. He was asked if he would like a "medal as being the best recruitment sergeant for independence we can wish for."
Prime Minister: "I see that the bonds of our Union are being strengthened throughout the entire time."
The Plaid Cymru MP informed Simon Hart, Welsh Secretary, that "two cabinet ministers had gone, his PPS (Parliamentary Personal Secretary) has gone, it's not business as usual. When will he [Mr Hart] go?"
Hart said it was "business as usual at the Wales Office" and that he was proud to say "we are continuing with the Levelling Up Fund. The Community Renewal Fund. And the Shared Prosperity Fund-investment across all parts of Wales".
The Welsh secretary asked her to join the effort to improve the lives and well-being of the people of Wales.
