Taiwan politicians know how to put on a good show. But the brawling and histrionics in parliament that have put Taiwan politics on the world map for the past 20 years are staged acts, legislators and political observers say.

They are planned in advance to generate media attention and garner favour with voters who like to see their representatives fight as hard as they can on tough issues.

Lawmakers even call up allies to ask that they wear sports shoes ahead of the choreographed clashes. They have been known to meet up afterwards for drinks.

"It's really a media event, staged for media coverage," said Nationalist Party (KMT) legislator Joanna Lei. "They have a strategy session, like a war plan."

The latest brawl erupted on May 8 when at least 40 MPs blocked the speaker from his podium to head off a vote on reconfiguring the Central Election Commission.

In the 1980s and 1990s, when minority parties had no procedural way to change governing bodies controlled then by the KMT, regular fights exposed inefficiency, crookedness and authoritarianism, said Shelley Rigger, an East Asian politics expert at Davidson College in the United States.

Today, despite full democracy, the fight strategy remains.

"It's true that politicians use (brawls) to excite their core supporters at home, but it's unclear how effective that is," Rigger said. "We do know, though, that it hurts the legitimacy of the democratic system as a whole. Mostly it's a delaying tactic."

In January, a brawl involving about 50 MPs who wanted to stop parliament speaker Wang Jin-pyng from accessing his podium lasted for four hours.

Shoes were thrown at the speaker, a microphone was ripped out and thrown across the chambers. MPs shoved and pulled one another's ties. Wang never made it to the podium.

Some of the brawling MPs turned to reporters and cameramen, yelling slogans to them and brandishing signs.

In 2005 one legislator needed stitches after he was struck by a mobile phone. Last year an MP used tear gas. Shouting exchanges occur almost every week on the parliament floor.

Some legislators says it is just a ploy to win votes.

"They just want to steal the spotlight going into the primaries," said People First Party MP Lee Hung-chun. "Parliament should be a sacred and noble place."