President Roh had tried to block an independent investigation

The parliament voted by a more than a two-thirds majority to block the veto, which had provoked some MPs to boycott parliamentary business.

President Roh is fighting for his political life after an aide was accused of taking illegal payments.

His popularity has plunged since he took office in February.

The GNP has a majority in parliament and, together with the other parties, it overturned Mr Roh's veto by 209 votes to 54, with two lawmakers spoiling their ballots and one abstaining.

The president's office expressed "regret" but indicated that the government would respect the assembly's decision.

POLITICAL FUNDING ROW 29/9 - Roh quits ruling party due to factional divides 13/10 - Roh proposes referendum on his rule 16/10 - Former Roh aide held on slush fund allegations 21/10 - GNP MP confesses to taking slush money 28/10 - State prosecutors begin inquiry 10/11 - National Assembly votes for independent inquiry 18/11 - LG offices raided as scandal widens 24/11 - Samsung subsidiary offices raided 25/11 - Roh vetoes independent inquiry 28/11 - Hyundai Motor affiliate offices raided Political scandal dogs South Korea

The vote not only clears the way for the independent probe, but also marks the end of the opposition's boycott - putting parliament back on track to handle more than 1,000 other bills pending, including the budget.

The GNP leader, Choe Byung-yul, attended Thursday's parliamentary session in a wheelchair because he has been on hunger strike to protest against Mr Roh's refusal to back parliament's call for an independent investigation.

It was the first parliamentary reversal of a South Korean presidential veto since 1954, and was carried out live on national television.

Parliament initially passed the bill calling for an independent inquiry on 10 November, but Mr Roh vetoed it later that month, arguing that state prosecutors needed to be allowed to finish their investigation first.

They have been looking into allegations of illegal political donations during last year's presidential election campaign.

A close aide of Mr Roh is accused of taking almost a million dollars from the SK Group, one of South Korea's leading conglomerates.

The investigation has been widened to include affiliates of other firms, such as Samsung Group and LG Group, and MPs from opposition parties.

Just 10 months after his election, Roh Moo-hyun's presidency is in trouble.

He has been condemned by politicians on the right for being too lenient with North Korea, and attacked by left-wingers for sending troops to help the US in Iraq.

Trade unions have mounted damaging strikes, and he has even broken with his own political party.

But correspondents say that the most damaging allegation is that some of his close aides have taken bribes or made illegal political donations.

President Roh came to office vowing to end the corruption that has often characterised relations between politicians and South Korea's powerful business conglomerates.