Unionist parties have recruited election experts to compose a single question for the independence referendum, challenging the SNP to join them.
Labour, Conservatives and the Liberal Democrats say the move will ensure a clear and neutral form of words for a straight Yes-No ballot, expected in 2014.
The SNP majority Scottish Government proposes to ask: "Do you agree that Scotland should be an independent country?"
First Minister Alex Salmond has already pledged that his preferred question will be rigorously tested by the Electoral Commission.
Critics, including Westminster's Scottish Affairs Committee, complain the wording invites a positive response.
There is also controversy over proposals to add another option to the ballot offering more devolution short of independence – the so-called Devo Max option.
The new panel will be chaired by Lord Sutherland of Houndwood and feature Dr Matt Qvortrup, an expert on constitutional issues, and Ron Gould, who investigated the fall-out from the troubled 2007 Holyrood election.
Their proposed question will also be submitted to the Electoral Commission for testing.
Scottish Labour leader Johann Lamont said: "The question to be put to the Scottish people in the referendum is too important to be left in the hands of politicians and I am confident that we have put together a group of experts who are able to draft a question which is balanced and fair."
The panel will convene in the next few weeks with the aim of presenting a proposed question to the Electoral Commission in the autumn.
Lord Sutherland said: "The most important political question for over three centuries which now faces the Scottish people concerns our constitutional relationship with other parts of the United Kingdom.
"A referendum which proposes such a choice requires a clear, understandable and unbiased question.
"To produce and vote upon such a question is the ultimate test of a mature democracy. For this to be done and seen to be done, it is essential to seek the help of the Electoral Commission."
Earlier in July Mr Salmond wrote to opposition party leaders telling them the Electoral Commission will test the referendum wording.
At the time, he said: "It follows a process which is identical to that in current Westminster legislation and confirms that Scotland's referendum will meet the highest international standards.
"By accepting the central role of the Electoral Commission, we have accepted the requests previously put forward by the opposition parties."
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