document: Under the  Wales Bill, currently going through Parliament, Welsh ministers could vary income tax by up to 10p in the pound, subject to a referendum.
  Mr Jones said that "on balance" a referendum would still be needed.
  But opposition parties suggested extra powers being offered to other parts of the UK could make a poll unnecessary.
  Assembly party leaders were giving evidence to the Commons Political and Constitutional Reform Committee, meeting in Cardiff Bay, which is holding an inquiry into the future of devolution.
  Mr Jones said: "Is there a need to have a referendum specifically on income tax devolution in Wales?
  "I think on balance I would say referendums still need to be held but given the pace of change elsewhere in Scotland...I am very wary of any suggestion, leaving aside what I've said on income tax, that every change in Wales needs to be approved by a referendum."
  Plaid Cymru leader Leanne Wood said AMs should decide on income tax, if English regions were to gain tax powers without referendums.
  "Given that there will be some tax powers offered, in all likelihood, to some of the English regions now, without the need for a referendum, we would argue that that changes the picture for Wales," she said.
  "Tax powers should be able to be triggered by the representatives of the people of Wales via this institution."
  Welsh Liberal Democrat leader Kirsty Williams also questioned the need for a poll, if parties put the issue of devolving income tax powers to Wales in their general election manifestos.
  "I really wonder whether that's necessary, especially if all political parties had it in their manifestos in May and people were elected on the basis of that," she said.
  Welsh Conservative leader Andrew RT Davies said he was "open-minded" about the need for a referendum, but noted that a specific question on income tax was included in Scotland's 1997 referendum which has not been put to voters in Wales.
summary: A referendum still needs to be held before income tax powers are devolved to Wales, First Minister Carwyn Jones has told MPs.