SEOUL - LAWMAKERS scuffled in the South Korean parliament on Thursday as opposition parties tried to block a ruling party move to introduce a bill to approve a free trade pact with the United States.

The melee erupted as dozens of opposition members of parliament and their aides attempted to push their way into a committee room where the ruling Grand National Party planned to introduce a bill later in the day to ratify the trade pact with Washington.

Security guards and aides from the ruling party tried to keep the opposition lawmakers away after the committee's GNP-affiliated chairman invoked his right to use force to 'keep order' in parliamentary proceedings - an attempt to introduce the trade bill despite opposition objections.

Television footage showed people from both sides shoving and pushing, and yelling at each other in a crowded hall at the National Assembly building amid a barrage of flashing cameras.

The main opposition Democratic Party says the trade deal should not be approved until the government comes up with better measures to protect farmers and others expected to suffer from increased US imports.

The minor opposition Democratic Labor Party joined forces with the Democrats in Thursday's attempt to block the bill.

The ruling GNP says the trade pact should be approved as early as possible because the country stands to gain much from the deal.

Amid concern the administration of President-elect Barack Obama might ask to renegotiate the deal, supporters of the pact believe early ratification by Seoul could also put pressure on the US Congress to do the same.

Seoul and Washington signed the agreement in April last year after 10 months of tough negotiations, but neither side has ratified it.

The accord to slash tariffs on goods and services is the largest for the US since the North American Free Trade Agreement with Canada and Mexico and the biggest ever for South Korea.

Nafta, signed in 1993, took effect the following year. -- AP