The Conservative leader says he would not block a request for a referendum on further law making powers for the assembly if he was prime minister.
David Cameron, who is visiting north Wales, ended months of speculation about his party's position.
He said a future Tory government would back a poll if a request was made.
Mr Cameron told BBC Wales that jobs and the economy should be the assembly's priority but he would not not stand in the way of a referendum.
He was speaking during a visit to Broughton in Flintshire.
My own view is let's roll up our sleeves and deal with the real priorities - jobs investment, getting the economy going - that is what I think people in Wales care about most of all
David Cameron, Conservative leader
Mr Cameron said: "I believe the priorities in Wales are getting jobs, are getting the economy moving, are dealing with the deficit.
"But I know people do want an answer to the question: What if the Welsh assembly voted to have a wider referendum on more law making powers of the assembly?"
Mr Cameron added: "Would a Conservative government, if one is elected, allow that to go ahead? And I can tell you the answer to that question is yes, we would. We wouldn't stand in the way of that request.
"But my own view is let's roll up our sleeves and deal with the real priorities - jobs investment, getting the economy going - that is what I think people in Wales care about most of all."
A Conservative government would hold a referendum if the assembly asked for one
Under the Government of Wales Act 2006, a two-thirds majority of the assembly needs to vote in favour of holding a referendum to ask the Welsh people whether it should have full law-making powers.
That request must then go to Westminster, where the Secretary of State for Wales decides whether to approve or deny the referendum.
The Shadow Secretary of State for Wales, Cheryl Gillan, has repeatedly refused to say whether a future Conservative government would agree to a request from the assembly.
By John Stevenson, BBC Wales political correspondent
Up to now the shadow secretary of state for Wales, Cheryl Gillan has repeatedly refused to say whether a future Conservative government would agree to a request from the assembly.
That in turn has led to accusations from the other parties that the Tories could block a referendum, even if that was the will of the assembly.
There comes a point where you can't hedge your bets, you can't go on...it just won't stick.
By making the announcement they effectively kill that criticism dead.
There is likely to be disquiet amongst certain sections of his party on his attitude on this.
This had led to accusations from the other parties that the Tories could block a referendum even if it was the will of the assembly to hold one.
Under the present system, law making powers flow from Westminster to the assembly on a case-by-case basis.
The system has been criticised in some quarters for being complicated and unwieldy.
Lack of understanding
But the Government of Wales Act contains provision for a referendum on full law-making powers in all devolved areas.
The All Wales Convention on further powers for the assembly is expected to report to the assembly government later this month on whether it should call a referendum.
The indications are that it will urge a poll earlier rather than later, because of a widespread lack of understanding among the public about the way the system currently operates.
However, it is unlikely that the process of calling a referendum could be completed before the next general election, expected in late spring 2010.
The assembly government is committed to a referendum on the issue by May 2011.
Plaid's Hywel Williams MP has responded to David Cameron's pledge that a future Conservative Government would not block a request from the Welsh Assembly Government for a referendum on further law-making powers for Wales.
Mr Cameron's comments come ahead of the All Wales Convention report, due to be announced on November 18.
Plaid Cymru MP Hywel Williams MP asked whether it could be assumed it was now a "cast iron guarantee".
He added: "Any incoming Conservative Government must respect the democratic wishes and voices of the Welsh people.
"I would expect Mr Cameron to give his assurances that the Tories would not employ any delaying tactics."
A recent YouGov poll suggested a majority of voters would vote 'yes' in a vote on extra powers for the assembly - but only by a small majority.
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