The party leader, Lord Alderdice, said in a message addressed to the continuing No campaign headed by the Reverend Ian Paisley: "We will make sure the wreckers do not have their way."

The Alliance Party draws its support from the nationalist and unionist communities and hopes to play a central role in the Assembly which will be elected on June 25.

Launching the manifesto Lord Alderdice said: "The Alliance Party is not only going to be at the heart of this new administration, it is going to be the entire focus around which the rest of politics is going to hang."

Pivotal role

In the new Assembly all the parties will be broken down into political camps.

For a vote to be carried it will need the support of more than 50% of the whole Assembly. Under measures designed to ensure parallel consent this figure will include a majority of both nationalists and unionists.

By being the only major non-sectarian political grouping, the Alliance believes it can hold sway, using its votes to give the Assembly a majority - if a majority of the nationalist and a majority of the unionists does not equal a majority of the Assembly.

This leads Lord Alderdice to claim his party has the opportunity to play not only a pioneering but a pivotal role.

Tax powers

He also said he wanted the Assembly to have tax varying powers - not just to raise taxation but also to lower it.

Lord Alderdice also unveiled a novel idea for dealing with the problem of having too many police officers if terrorist violence does finally end - export them.