The Brexit Party will campaign in next year’s Senedd election to scrap the current system of devolution.
Mark Reckless, leader of the party’s group in the Welsh Parliament, said “devolution has gone so much further” than some people thought it would.
He is proposing a directly-elected first minister and getting rid of members of the Senedd (MSs).
The last Welsh barometer poll suggested around 22% of people supported abolishing the Welsh Parliament.
But in a multiple-choice question, the highest level of support was for leaving the settlement as it is (24%), followed by a Senedd with more powers (20%) and Welsh independence (16%).
Speaking to the BBC Politics Wales programme, Mr Reckless said under his plans a directly-elected first minister would be scrutinised by Welsh MPs.
He questioned the value of having the Senedd and its members in addition to MPs in Westminster.
“A lot of people who haven’t engaged with devolved politics now see the powers this place has, and many of those people would prefer to be governed on a UK basis rather than having things done differently in Wales just for the sake of it, as so often has been the case under Mark Drakeford,” he said.
The Brexit Party’s four MSs are its biggest group of politicians now that the UK no longer has members of the European Parliament (MEPs) following its departure from the European Union.
Mr Reckless said party leader Nigel Farage is “consulted over key decisions… but he doesn’t micro-manage us here”.
He said he did not “rule out” a potential rebrand of the party, as had been reported.
The Brexit Party has been very critical of the Covid-19 lockdown measures.
Asked if he believed there should be another Wales-wide lockdown, he replied: “We think it’s much better to trust people’s judgment. The individual knows best.
“I think what we’ll see is that many more people will stay at home.
“But the idea that you tell people how many times they should exercise… I don’t believe there’s science for that.
“I also believe that interference with people’s lives is so great when the evidence is so very limited.”
Pushed on whether he was against another lockdown in the event of a steep rise in coronavirus cases, he said: “I think it should be a last resort, and I think the time when you really need to do that is if infections are at such an extent that it threatens the capacity of our health services to cope.
“I think that is a good reason for closing schools, for government intervention, in order to stop that.
“But actually, I think when we look back it was that handwashing, it was a degree of social distancing, it was more people staying at home voluntarily that saw the infection rate begin to come down and meant that capacity in the health service wasn’t overcome in that way.”
BBC Politics Wales is on BBC One Wales at 1015 BST on Sunday, and on BBC iPlayer shortly after it is broadcast.