Rishi Sunak and Liz Truss have attacked Mark Drakeford and his Welsh Labour government at a Tory leadership hustings.
Frontrunner Ms Truss accused the first minister of being a "low energy version" of Jeremy Corbyn who was "ashamed of our history".
Meanwhile Mr Sunak said he would be an "activist prime minister" who would call out "failures of devolution".
The pair answered questions from party members in Cardiff on Wednesday night.
Mr Drakeford told BBC Wales that he did not have time to watch the event and had "only seen reports of it".
But, interviewed by Newyddion S4C, he said: "Of course, the two contestants were welcome to make one of their rare visits to Wales and there's nothing that I could say about either of them that they haven't already said about each other."
In his opening speech, the former chancellor attacked plans for more Senedd members in Cardiff Bay, saying money should be spent on cost of living issues instead.
He said a Welsh government freeze on road building projects, which ministers say is necessary to reduce carbon emissions, would cause "enormous economic self harm".
Mr Sunak attacked Welsh Labour's record, saying that "in spite of receiving 20% more funding, here in Wales waiting lists are the worse in the United Kingdom".
He indicated he was opposed to more devolution for the Senedd and said he would be an "activist prime minister when it comes to Wales".
He said: "We need to be more prepared to call out the failures of the devolved government here, because this path of onward devolution has not worked in actually delivering better health care and education".
Mr Sunak added: "If the UK government is sending billions of pounds over to Wales, and it's being squandered, it's not being spent properly, and children are not being taught properly in schools and people are waiting unacceptably long for health care treatment, we need to call that out and we need to make sure we improve it."
In her speech, Ms Truss said: "The fact is that there are too many people in this country who are ashamed of our history, who talk our country down, who say the best days are behind us. They are completely wrong.
"I'm afraid one of them is Mark Drakeford."
"Whether it's stopping the M4 relief road, whether it's whacking a tax on our tourist industry, I will crack down on his negativity about Wales, and about the United Kingdom."
Ms Truss promised to change the Treasury's funding formula to get investment "into places that have been left behind".
"We need to help level up our country," she said, "and you know that there are parts of Wales where it's very difficult to get a mobile phone signal, it's very difficult to get broadband.
"It's difficult to get on a train that goes anywhere very fast - and in particular, north Wales has been left behind."
She said she would build the M4 Relief Road. The project was ditched by the Welsh government, which has responsibility for motorways in Wales, in 2019.
A small group of climate change protesters greeted arriving Conservatives at the All Nations Centre ahead of the event.
Analysis by David Deans, BBC Wales political reporter
If your question was whether Rishi Sunak will devolve more powers to the Welsh Parliament as prime minister, it seems clear he will not.
He told Tory members - often assumed to be more devo-sceptic than some of their elected members in Cardiff Bay - that the answer to problems in Wales was "not more devolution", and intimated that he would get more involved in Welsh affairs.
Would he intervene in health and education? There was nothing concrete - but he said he would be an "activist" prime minister - the suggestion was there.
Sunak walked into the All Nations Centre with what sounded like a plan to win over sceptical Welsh Tory voters. But there was no arms race on the subject with front runner Liz Truss.
She had little to say when it came to the constitution of Wales - the nearest she got to the subject was where she said it was right that the Welsh government run the NHS - which it has since 1999 and is only interesting because of the comments of her rival.