A new opinion poll shows Hamas, the organisation behind the biggest proportion of Israeli deaths in suicide bombings over the last five years, and Fatah, the organisation which has dominated the Palestinian Authority (PA) since it was formed a decade ago, effectively heading for a dead heat.

With most Palestinians due to vote on Wednesday, a poll by the Jerusalem Media and Communications Centre showed Fatah capturing 32.3% of the vote, compared with Hamas on 30.2%. This was well within the margin of error of 3.5%, underlining how tight the race will be.

Fatah might be forced to rely on a coalition with two independent groupings, both of which oppose violence against Israel, to maintain even a slender majority in the Palestinian Legislative Council. The poll showed one of these, the Independent Palestine party, headed by Mustafa Barghouti, coming third with 12.6%.

Hamas regards its record of attacks on Israel, which it claims forced the Israelis to withdraw from Gaza, as one of its main electoral assets. So far, however, it has largely held to the truce negotiated with the Palestinian President, Mahmoud Abbas, last year.

Abbas has long hoped that Hamas's enthusiastic . . . and, compared with Fatah, highly disciplined . . . participation in the political process for the first time would help to wean it away from its past strategy of militant violence. But his other prediction to President George Bush, that a clean and decisive defeat of Hamas in the elections would help to restore his authority among Palestinians, now looks misplaced.

Hamas refused to contest the last legislative council elections in 1996 or the presidential election in 2005. It has given little away during this campaign about how it would use its new-found power within the Palestinian parliament, or whether it would seek ministerial positions. Some analysts doubt that Hamas would want to take overall control of the PA, even if it had the majority to do so.

This in turn has left the US and the EU uncertain about how it would handle a PA which had Hamas, or proHamas ministers, in its ranks.

Javier Solana, the EU's foreign affairs envoy, said last month that Europe would freeze aid if Hamas, which is proscribed as a terrorist organisation, was represented in the government. The US Congress also voted by a large majority to halt aid in such circumstances. Some Western governments, however, are debating whether it would be better to make aid conditional on Hamas agreeing to refrain from armed attacks on Israel.

Meanwhile, the 58,000 members of the Palestinian security forces began to vote yesterday amid accusations by Hamas that some commanders had ordered their men to vote for Fatah.