DUBLIN - Just 25 percent of Irish voters plan to back the European Union's planned reform treaty in a referendum next year when a "No" vote from one of the bloc's smallest countries could topple the project, a new poll showed.

The survey in Monday's Irish Times newspaper showed some 62 percent didn't know how they would vote or had no opinion while 13 percent intend to reject the treaty.

Despite the large numbers of undecided voters, the newspaper noted that support had effectively halved since a comparable poll in March 2005 when 46 percent of people surveyed said they planned to vote in favour of the now defunct EU constitution.

The reform treaty agreed by EU leaders last month replaces the planned constitution which was rejected by French and Dutch voters in 2005, triggering an institutional crisis in the 27-country union.

This time round Ireland, whose own constitution can only be amended by a referendum, is expected to be the only country to ask voters directly to back a treaty that needs to be ratified by all EU states if it is to take effect from 2009 as planned.

Ireland, whose economic boom over the last decade was underpinned in part by EU funding, is generally seen as being among the region's most pro-European countries but that has not always guaranteed success at the ballot box in the past.

In 2001 Irish voters rejected the Nice Treaty designed to enable EU enlargement, forcing the government to hold a second vote that was widely criticised as undemocratic at the time and is unlikely to be an option in 2008.

The Irish Times said support for the new reform treaty was strongest in Dublin and the surrounding area and considerably lower in other regions, reflecting disillusionment in rural communities over EU policies on agriculture.