They fear that they would be losers under any devolution of tax-raising powers.
The finance secretary, Mark Drakeford, said: "This is an historic milestone in the devolution of tax powers to Wales.
In his Budget speech, the Chancellor argued that the new Government was delivering "major devolution of tax and welfare powers" to Holyrood.
Labour is concerned that the devolution of tax powers has not been fully thought through and is part of the Government's "English votes for English laws" agenda.
Under the plan, which was first signalled by Mr Osborne at the weekend, details of fresh devolution of tax and welfare powers would be agreed by late November and legislation drafted next January.
These include pressing for spending increases, blocking Trident, reversing the Health and Social Care Act 2012 and ensuring the full delivery of the Smith commission recommendations for far greater devolution of tax and welfare powers to Holyrood.
Labour and the Liberal Democrats are edging towards a post-referendum pact on further powers for Scotland, which could see a deal to agree much greater devolution of tax and welfare powers from Westminster.
It said devolution of tax powers would encourage and improve the quality of debate within and outside the Welsh government about its policies and programmes.
"While the results show clear support for the devolution of tax and borrowing powers, we must be mindful as a commission of the concerns they also reveal.
Pollsters ICM said there was evidence that people did not fully understand the current tax arrangements, but that a picture was emerging of a public who, if forced to choose, would opt for the devolution of tax powers.
