Colombo, April 21 (IANS): The Sri Lankan government on Tuesday opposed the parliament speaker's decision to summon the country's anti-graft chief over her move to question the former president for bribery allegations.

Parliament Speaker Chamal Rajapaksa, who is also a brother of former president Mahinda Rajapaksa, summoned director-general of the Commission to Investigate Allegations of Bribery or Corruption, Dilrukshi Wickramasinghe on Monday after a group of opposition parliamentarians staged a protest in parliament over Rajapaksa's bribery allegations, Xinhua news agency reported.

Deputy Foreign Minister Ajith Perera said that the decision by the speaker to summon the commission chief was completely unacceptable as the anti-graft panel functioned independently.

The protest continued overnight with over 70 parliamentarians refusing to leave the parliament building.

The former president's spokesman, Rohan Weliwita said despite media reports that Rajapaksa had been summoned over allegations that he had bribed a former member of the ruling United National Party to join him before the January presidential elections by offering him a ministerial post, such a move was not illegal as he was the president at that time.

Meanwhile, 113 opposition parliamentarians, all supporters of Rajapaksa, signed a petition on Tuesday against the commission chief Wickremasinghe.

The parliamentarians complained that the commission had overstepped its mandate by summoning the former president and his brother Gotabaya Rajapaksa, who was also the defence secretary during Rajapaksa's decade-long tenure in office.

Gotabaya Rajapaksa has been summoned to appear before the commission on Wednesday.