Taiwan's opposition legislators have thrown pig guts and exchanged blows in parliament amid a heated row over the easing of US pork imports.

They say a recent government decision to allow the import of US pork containing ractopamine - an additive banned for pig use in Taiwan and the European Union - is a health threat.

The ruling party denies the charge and called for a return to rational debate.

It is not uncommon for brawls to erupt in Taiwan's parliament.

Lawmakers from Taiwan's main opposition Kuomintang (KMT) party hurled buckets of pig intestines towards Premier Su Tseng-chang on Friday to stop him from taking questions in parliament.

Some also exchanged blows in a "short but vicious" encounter between KMT legislators and Chen Po-wei from the small Taiwan Statebuilding Party, reported Reuters news agency.

It said the ruling Democratic Progressive Party (DPP) condemned the "disgusting" protest, calling it a waste of food that "stank up" parliament as they urged a return to rational debate.

Washington has welcomed the August decision by Taiwanese President Tsai Ing-wen to ease US pork imports from 1 January.

But the move has galvanised the opposition, which has tapped into public concerns over food safety after a series of recent scandals.

Last weekend in the annual "Autumn Struggle" demonstrations, protesters held aloft a giant inflatable pig in opposition to the imports.

The additive ractopamine is currently banned for pig use in Taiwan, as well as in China and the European Union, due to concerns about safety for animals and humans.

Taiwan has become somewhat notorious for fights breaking out on the parliamentary floor.

The Legislative Yuan - or parliament - has seen punching, hair pulling, and the throwing of plastic bottles and water balloons over the years.

In one particularly heated fight in July 2017, legislators lifted up and threw chairs at each other as they argued over an infrastructure spending bill.