At the beginning of the session, a group of MPs demanded a re-vote on the candidacies, which were approved Thursday.
Ex-speaker Omurbek Tekebayev, co-chairman of the For Reforms opposition movement, slammed the move, saying bribes were behind it.
The accusation provoked a fierce reaction from MP Akmanbek Keldibekov, and the two MPs traded blows following an exchange of words.
Speaker Marat Sultanov, who tried to separate the combatants, was himself dragged into a scuffle with Tekebayev before fellow lawmakers intervened to end the brawl.
The parliament's oldest deputy, Doronbek Sadyrbayev, said the incident reflects the situation in the country as a whole.
"Not only deputies, but the whole country is in a fever," he said.
Tekebayev's For Reforms movement was the engine behind a week-long opposition rally in the Central Asian country's capital, Bishkek, in early November, which forced President Kurmanbek Bakiyev to sign a new Constitution curbing his powers in favor of parliament.
