Talks aimed at thrashing out the arrangements for a referendum on Scottish independence will be held later.
The Scottish Secretary Michael Moore and Scotland's First Minister Alex Salmond will meet in Edinburgh.
It is the first of a series of discussions designed to resolve disagreements on how the ballot should proceed .
Prime Minister David Cameron is also due to hold a meeting with Mr Salmond over the coming days.
There are a number of key outstanding differences between the Holyrood and Westminster Governments on the referendum, primarily with regard to the number of questions on the ballot paper.
Mr Cameron insists there must be only one question - independence, yes or no? - but Alex Salmond's SNP has not ruled out a second question on so-called Devo Max, a beefed-up version of devolution whereby tax powers would be transferred to Holyrood.
The Westminster coalition is also opposed to the SNP's proposal to give the referendum vote to 15 and 16-year-olds.
It has warned that Holyrood does not have the power to hold a referendum without the permission of the Westminster Government and that, without its consent , any ballot could be blocked by the courts.
This is disputed by the SNP, which insists it has the power to hold a consultative referendum.
It proposes to hold a ballot in the autumn of 2014 and last month, Alex Salmond announced the question he proposed to ask the Scottish people: "Do you agree that Scotland should be an independent country."
Both Westminster and Holyrood administrations are conducting their own separate consultations into the referendum process.
Ahead of the Salmond-Moore meeting, Scottish Labour leader Johann Lamont told Sky News: "This cannot be just another photo opportunity or box-ticking exercise for the First Minister - we need meaningful discussions on a fair, transparent and decisive referendum.
"There is a real chance to end the games and bring some certainty to this process so that all of Scotland can have confidence in our referendum and move on to the debate over the issues."
