Northern Ireland's ruling coalition of pro-British unionists and Irish nationalists appeared set to be re-elected on Friday, vote tallies and early results showed, an outcome that would cement the peace process.

Former bitter rivals the Democratic Unionist Party (DUP) and nationalist Sinn Fein said tallies showed support for their power-sharing government was up compared with elections four years ago that ushered in a period of unprecedented stability.

"There is no question now that the DUP and Sinn Fein will lead the next government," said Margaret O'Callaghan, professor of politics at Queen's University in Belfast. "The post-peace process stability has been maintained."

The DUP and Sinn Fein together secured 20 of the first 26 seats in the 108-seat assembly, which controls policing, health and education. Rival parties said their tallies showed the governing parties improving on their results four years ago.

"It appears at this stage that the electorate are charging Sinn Fein and the DUP to take this vitally important process forward for another four years," Deputy First Minister Martin McGuinness of Sinn Fein told Irish state broadcaster RTE.

The parties formed a government in 2007 despite the fact that mainly Catholic Sinn Fein is dedicated to unification with the Republic of Ireland while the predominantly protestant DUP wants to remain in the United Kingdom.

The small non-sectarian Alliance party joined the coalition later.

Tallies indicate "the parties that seem to be doing well are DUP, Sinn Fein and the Alliance Party," First Minister Peter Robinson, head of the Democratic Unionist Party told BBC television.

"There is no coincidence that these are the parties working together in the executive. There is no real opposition to what we are doing," he said.

The re-election of the government would represent a rebuff to militant Irish nationalist groups opposed to the 1998 peace deal that ended 30 years of armed resistance to British rule.

Police were placed on high alert after a police officer was killed by one of the so-called "dissident" groups in a car bomb earlier in the campaign, but no security alerts were reported on voting day.

No candidates representing dissident militants were expected to secure representation in the election, a sharp contrast from the wide support enjoyed by Sinn Fein as they supported an armed campaign by the Irish Republican Army in the 1970s and 1980s.

Officials said final results, which are based on a complex system of proportional representation, would not be announced before Saturday.

Reuters