BUDAPEST -- Hungary's Parliament failed to agree changes to media laws on Tuesday, threatening to disrupt the country's bid to join the European Union by 2004.

In a political spat just weeks ahead of national elections, the opposition Socialists ended a parliamentary boycott for the Assembly's last pre-election session, only to oppose amendments to the media law, one of the outstanding policies the EU wants cleared up before admitting Hungary.

Without changes to the media law, Hungary cannot close the audiovisual "chapter" in its EU membership negotiations.

The ruling center-right coalition had hoped to push through the changes -- on allocating seats on public boards for media such as state radio and television -- in a fast-track vote.

But it failed to get the majority needed to hold the vote.

The Socialists, who have been running neck-and-neck in recent opinion polls with Fidesz, the senior coalition partner, withdrew from parliamentary business earlier this month, accusing Prime Minister Viktor Orban of calling them "traitors".

Hungary has said it hopes to finalize its EU accession talks this year and join an enlarged bloc by 2004. A Reuters survey of economists and analysts earlier suggested a first wave of EU enlargement was more likely to be delayed until 2005.

The political parties have been wrangling for years over the number of seats each should have on public media boards.

These are normally divided evenly between government and opposition, but the Socialists, by far the biggest opposition party, disagree with demands by the much smaller far-right Justice & Life Party (MIEP) for more seats.