The Secretary of State for Wales is warning that any plans to increase the Welsh assembly's powers will have to be agreed by MPs at Westminster.
Peter Hain says the number of Welsh MPs should remain at 40
Peter Hain said he was prepared to listen to the arguments in favour of increased powers but that there should not be seen as a solution to tackling Wales' problems.
"MPs will look, as I am doing, at any case for change on its merits," Mr Hain told BBC Radio Wales.
"If a persuasive case is put then we will be convinced"
The Neath MP is entering the devolution debate amid growing speculation over the report of a commission set up to consider the case for transferring more powers from Westminster.
It is thought that the Richard Commission, which is likely to report in the spring, will recommend increasing the number of assembly members from 60 to 80 - and giving them more law-making powers.
But Mr Hain has said that a Scottish-style Parliament is not on the agenda.
The commission has spent several months canvassing the opinions of members of the public in a series of seven public meetings.
It will eventually make recommendations on issues including the Welsh electoral system and whether the assembly needs greater authority, similar to the law-making powers of the Scottish Parliament.
Mr Hain has said that the number of Welsh MPs should remain at 40.
He did not, he said, want a repeat of the Scottish experience, where plans to reduce the number of MPs at Westminster have caused problems for Labour.
He added that there had to be a consensus for any change between Westminster and Cardiff.
As things stand, changes to the devolution settlement can only be made in Westminster.
Any change in tax-varying poweres would have to go to a referendum, said Mr Hain.