Stephen Fitzpatrick, Jakarta – East Timor's court of appeals will ratify today the results of the country's parliamentary election, setting the stage for a potentially brutal showdown between former ruling party Fretilin and the powerful coalition opposing it.

Although Fretilin gained the highest simple majority in the national poll, with 29 per cent of the vote, it will probably have to stand aside in the parliament for an alliance headed by former president Xanana Gusmao's National Congress for Timorese Reconstruction (CNRT).

Signs that this will not happen easily or peacefully intensified at the weekend, with Fretilin secretary-general Mari Alkatiri declaring his party was "open to any party to form a coalition, but if they are against us, Fretilin will form a government". He had previously insisted his party would not enter any kind of national unity government, acknowledging the detrimental effect this could have on the country's emerging democracy.

However, since provisional results from the June 30 election began showing that Fretilin, despite being well ahead of Mr Gusmao's 24 per cent result, could not form government alone, Mr Alkatiri has been fighting a rearguard action in public, insisting his party retains the right to rule.

The constitution requires the grouping that forms government to hold a clear majority in the 65-seat house – something no party achieved alone. Fretilin's result gives it 21 seats, and CNRT's just 18.

However, Mr Gusmao's party is now expected to go into coalition with the Social Democratic Association of Timor-Social Democratic Party alliance (11 seats) and the Democratic Party (eight seats).

The ASDT-PSD alliance is headed by former Indonesian-era governor Mario Carrascalao, who still carries significant clout in the politically riven society, and the PD by former guerilla fighter Fernando "Lasama" de Araujo, who has strong support from veterans of the 24-year armed struggle against Jakarta.

President Jose Ramos Horta has been conducting intense negotiations with all groups, fully aware that any spoiling action by Fretilin could tip East Timor back into the kind of imbalance that led to extreme violence last year.

But Mr Ramos Horta, who replaced Mr Alkatiri as prime minister at the height of the troubles last year before becoming President in elections this year, is aware there is enough ambiguity in the constitution to produce a power vacuum.

The country's founding document says a prime minister must be nominated "by the most-voted party or by the alliance of parties with a parliamentary majority" and then appointed by the president, "having heard the political parties represented in the parliament".

Mr Ramos Horta said at the weekend that he would approve a prime ministerial suggestion based on "which of the various parties can persuade me they are in a position to form a government that is stable, that is long-lasting".

He has repeatedly called for a government composed of all East Timor's major political elements, but has also backed Mr Gusmao for the prime ministership.