By Sarah Toms BBC News, Manila

Spokesman Ignacio Bunye played the recording to the media

Philippines President Gloria Arroyo has released a tape she says the opposition doctored to support claims that she won last year's election fraudulently.

The opposition has called repeatedly for the tape to be played in public. Now it has been aired to the media by a presidential spokesman.

In it, Mrs Arroyo can be heard apparently pressing the election commission head to alter the tally.

The president says she did nothing of the sort.

The president's spokesman said the conversation had been altered and dismissed the tape as the latest attempt by the opposition to destabilise the government.

Still, Monday's allegations come at a difficult time for President Arroyo.

Her ratings have slumped to a record low amid accusations that members of her family have taken pay-offs from illegal gambling syndicates. They deny any involvement.

Filipinos are also angry about rising prices and persistent corruption.

In the recording, Mrs Arroyo allegedly asks the election official if her lead could fall below one million votes during the count from the 2004 election.

The official says her lead had fallen but that some wards had still to be counted. The official then says "we will do our best".

The final election tally gave President Arroyo a winning margin of more than one million votes over her strongest rival, Fernando Poe Jr.