A Sinn Fein member is likely to be appointed as Speaker of the Assembly tomorrow to replace Willie Hay of the DUP.
The First and Deputy First Minister will also take office on the same day. The rest of the ministerial teams will not be chosen until Monday.
The delay is partly to allow the parties to work out a joint approach on thorny issues, or ones that involve co-operation between several departments.
These issues include education, the Review of Public Administration (which will reduce the number of councils), and the Cohesion, Sharing and Integration Strategy.
The discussions are intended to map out a common agenda which will avoid friction and speed up decision-making.
The post of Speaker is constitutionally neutral, but it is regarded as symbolic by Sinn Fein that a nationalist should fill it.
In the past there have been nationalist deputy speakers like John Dallat of the SDLP and Francie Molloy of Sinn Fein.
In 2007 Sinn Fein supported Mr Hay, who its accepts has discharged his duties impartially, on the foot of a statement by Ian Paisley that said “we will support someone from the other side of the house in the next Parliament”.
Sinn Fein is now calling in that pledge, but some in the DUP are saying that the post could instead rotate halfway through the Assembly term.
Between now and Monday there will be horse-trading on ministries.
The DUP is likely to take Finance, and also has its eyes on Education — which is sought by many parties — and Health.
Sinn Fein may pick Enterprise Trade and Investment over Education if it is assured that the 11-plus will not be restored.
There have been suggestions that Martina Anderson and John O’Dowd of Sinn Fein will be appointed ministers.