Jose Ramos-Horta has won the backing of a key powerbroker ahead of next month's presidential vote in East Timor by agreeing to call off a manhunt for a fugitive rebel soldier wanted by Australian troops, party officials have said.

Mr Ramos-Horta and parliament chief Francisco "Lu-Olo" Guterres will contest next month's run-off after they failed to win a majority in the April 9 election, East Timor's first since independence in 2002.

Fernando "Lasama" de Araujo, who finished third in the election with 19.18 per cent of the vote for the opposition Democrat Party, has publicly backed Mr Ramos Horta at a party rally today.

In return for the support, Democrat Party officials have said, Mr Ramos-Horta has agreed to resume talks with and call off the search for Major Alfredo Reinado, blamed for his part in last year's unrest which resulted in Australian and other international peacekeepers being sent in.

Speaking to Democrat supporters in the capital Dili and flanked by Mr Ramos-Horta, Mr Lasama said the Nobel laureate, as president, would safeguard democracy, unite the people and promote human rights.

"Therefore, I call on all PD (Democrat Party) activists to vote for Ramos-Horta in the upcoming May 9 election," he told about 100 supporters. "Yesterday (Wednesday) the PD leadership reached a decision, by acclaim, to throw its support behind Ramos-Horta."

Impoverished Timorese hope the run-off will pull them from a cycle of violence and turmoil that has beset the country since it voted for independence from Indonesian rule in 1999.

In the run-off, Mr Ramos-Horta faces Mr Guterres, candidate for the ruling Fretilin party, which has been a force in the country since the struggle for independence.

Mr Ramos-Horta, the nation's current Prime Minister, thanked Mr Lasama and the party for their support. "Even though the party was set up just a few years ago, it has already helped build the country and help democracy and freedom in this country," Mr Ramos-Horta told the crowd.

Mr Ramos-Horta has already clinched the backing of three other candidates who bowed out after the April 9 round.

East Timor voted for independence in a UN-sponsored referendum in 1999, triggering an orgy of killing by pro-Jakarta militia before independence was declared in 2002.

Foreign peacekeepers have been on the streets for nearly a year after gang violence left 37 people dead and sent 150,000 more fleeing their homes.

Major Reinado has been on the run since his escape from a Dili prison last year. Elite Australian troops attacked his mountain hideout earlier last month in a failed bid to capture him. Five of his armed supporters were killed during the raid on his hideout, which triggered rowdy protests.