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 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.
"This is an opportunity to agree on one of the fundamental parts of the referendum process in a way that is above party politics and partisan views, and the door is still open for Alex Salmond to join with us and take this forward on a cross-party basis."