The Welsh assembly should get wider powers if Scotland votes for independence, First Minister Carwyn Jones has suggested.
He said Wales' relationship to the rest of the UK would need a "radical reconsideration" if the Scots back independence at a referendum.
Independence or full fiscal autonomy would make the UK very different, he said in a lecture in Aberystwyth.
But he said further devolution for its own sake did not appeal to him.
Delivering a lecture on the future of devolution, Mr Jones said he was cautious about arguments that said Wales should get whatever Scotland has.
The so-called "devolution max" option - which would make Scotland fully responsible for its own finances - was not right for Wales, he said.
The SNP government in Edinburgh will hold a referendum on Scottish independence near the end of the five-year parliament.
Mr Jones speculated about what would happen if Scottish voters "change the rules of the game".
"The United Kingdom as we currently understand it would become a very different thing indeed, and Wales' constitutional relationships within it would require a much more radical reconsideration," he said.
He said "it might be that a more generous transfer of legislative competence to the assembly" is needed.
He suggested it could be based on a similar model to the Scottish parliament's current powers, underpinned by a separate legal jurisdiction for Wales.
With the support of a "more equitable system of devolution finance" the set-up could "provide the basis for a new constitutional settlement for Wales within a restructured UK", he said.
He said the Silk Commission into the future of Welsh devolution may need to make recommendations on the basis of different outcomes to the Scottish referendum.
Wales had a "lop-sided" system of devolution, with law-making powers granted by a referendum in March, but far less power over its finances.
He repeated the Welsh government's view that it is short-changed by the Treasury's system of funding the devolved administrations.
There was a pressing need to give the Welsh government borrowing powers, he argued, citing a big cut in its capital spending budget as a result of a UK-wide public spending squeeze.
He warned of a "race to the bottom" if the regions and nations of the UK controlled their own corporation tax rates.
He added: "To be clear and to avoid misunderstanding or ambiguity, I am not advocating income tax powers, but neither do I have a closed mind to debate about the best ways to finance Wales over the long term.
"In any case, on matters as fundamental as income tax, it is the people of Wales who should always have the last word."
The Welsh Labour leader stressed that he would not agree to any power being handed back from Cardiff to London, so-called "repatriation".