The count will not be completed until June

According to figures from the National Citizens' Movement for Free Elections (Namfrel), Mrs Arroyo's lead has been cut from 10 percentage points to four.

With more than half the vote counted, Namfrel said Mrs Arroyo had 41% against 37% for her close rival Fernando Poe Junior, a former film star.

The official result of the 10 May poll will not be known until June.

Namfrel is an independent monitor authorised by the government to count ballots and produce its so-called "quick count", which has been accurate in predicting previous election results.

Namfrel said that by the end of Thursday, it had tallied results from more than half the election precincts. Mrs Arroyo had 7m votes compared to Mr Poe's 6.3m. The three other presidential candidates were trailing far behind.

PRESIDENTIAL HOPEFULS President Gloria Macapagal Arroyo Film star Fernando Poe Junior Former police chief Panfilo Lacson Former education secretary Raul Roco Evangelical preacher Eduardo Villanueva Profile: Gloria Arroyo Profile: Fernando Poe Jnr

Earlier in the week, Namfrel figures showed Mrs Arroyo comfortably ahead, but Mr Poe appeared to have closed the gap as results came in from the capital, Manila, and from Mindanao in the south.

Mr Poe's supporters are continuing to dispute the fairness of the election.

They have accused Mrs Arroyo's camp of numerous irregularities, including vote-buying and harassment of voters.

Mr Poe, who has already declared himself the winner, has been touring the southern island of Mindanao.

In all, the result of the elections will decide the president, vice president, 12 senators, 200 members of the House of Representatives and 17,000 posts such as governor and town mayors.

If Mrs Arroyo wins the race for the top job, she will be given her first real mandate.

Although she has been in power for three years, she inherited the presidency from Joseph Estrada, who was ousted as leader by street protests in 2001.