With a date set for Ulster elections the major parties are gearing up for a hard fought campaign with high stakes.

Both the main nationalist and unionist parties are under threat, with the prospect of a new assembly suspension hanging over the result.

It is thought that a breakthrough by the anti-Good Friday agreement Democratic Unionist Party could force the government to close down the Stormont assembly.

Ian Paisley's DUP is challenging the Ulster Unionist Party to be the biggest single party in Northern Ireland.

David Trimble's UUP won 26 seats in the 1998 elections, with the DUP returning 20 MLAs.

Since then, however, internal splits within the UUP have widened .

And confidence in the devolution process among the majority unionist community has waned as the IRA has stalled on its arms decommissioning pledges.

That could boost Paisley's prospects and his party is likely to play on divisions between Trimble and his colleagues.

However the prospect of continued direct rule could hold the DUP back, with the Stormont executive generally popular among voters.

Paisley will promise to renegotiate the Good Friday settlement if he tops the poll, imposing tougher sanctions on continued terrorist activity.

Trimble will argue that no such deal is on the table from either London or Dublin and only a pro-agreement voice can lead the assembly executive.

But he will campaign on a "Simply British" ticket in a bid to show he has no truck with those who see the assembly as a stepping stone to a united Ireland.

Meanwhile on the nationalist side, an insurgent Sinn Fein is threatening the SDLP's dominant position.

Sinn Fein won 18 seats in 1998, six behind the more moderate SDLP.

Sinn Fein has continued to grow in popularity, despite being the political wing of the IRA.

Leaders Gerry Adams and Martin McGuinness have established themselves as credible politicians despite becoming embroiled in the Stormont spy-ring row.

While Mark Durkan's SDLP could see its overall popular vote drop, the single transferable vote electoral system could save his status as the senior nationalist figure.

Assembly seats are allocated on a proportional basis - but the SDLP's widespread popularity could mean it picks up second and third preference votes from supporters of smaller parties.

That could leave Durkan ahead of Sinn Fein in terms of total Stormont seats, giving him more ministers in the executive and the title of deputy first minister.

As the election date approaches the government hopes the moderate wings of both republicanism and unionism will win through.

But if Sinn Fein and the DUP are returned in larger numbers then the assembly and the devolved government will once again be thrown into crisis and confusion.

With competition for votes fierce, the smaller Ulster parties may suffer from the squeeze at the top.

However the electoral system is kind to minor parties and several will hope to win representation.

The Alliance Party will battle to hold on to its six MLAs and its position of assembly speaker.

The cross community party lost votes to the UUP in the 2001 general election though as supporters sought to bolster Trimble's position.

The UK Unionist Party is likely to lose some or all of its five seats although leader Bob McCartney could hold on.

Since 1998 the party has performed poorly and been riven by internal splits.

The United Unionist Assembly Party has been effectively outflanked by the DUP since 1998 with one of its MLAs joining Paisley's party and the other two set to lose to him this year.

The loyalist-linked Progressive Unionist Party could suffer from its association with paramilitary feuding but leader David Ervine is an established figure who should hold at least his own seat out of the party's two current seats.

The Women's Coalition will do well to keep its two MLAs but surpassed expectations in 1998 and is a popular second or third preference choice.