Sri Lanka's Maithripala Sirisena publicly rebuked his intelligence chief Sisira Mendis. (File)

Sri Lanka's president publicly rebuked his intelligence chief on Thursday after he told a parliamentary panel that the Easter suicide bombings in which 258 people died could have been avoided.

The testimony appeared to put President Maithripala Sirisena in a poor light by implying he had not held National Security Council meetings to review threats such as the attacks carried out by ISIS.

Authorities shut down a live broadcast of Chief of National Intelligence Sisira Mendis giving evidence to the parliamentary panel without giving an explanation.

In a statement, Mr Sirisena denied claims by Mendis that the country's highest security body had not met as often as it should have around the time of the attacks blamed on ISIS-backed militants.

Mr Sirisena, who is also defence minister, said in a statement he held NSC meetings twice a week, contradicting Mendis who told parliament the last meeting was on February 19, more than two months before the April 21 bombings.

Mr Sirisena said he met with the national police chief and his top brass 13 days before the Easter Sunday attacks and no officer raised warnings which had been relayed by India.

Official sources said neighbouring India provided details of planned attacks based on information from a terrorist in Indian custody.

"The precise information provided by a friendly country was never brought to the attention of the president by the secretary to the ministry of defence, the inspector general of police or any other officer," Mr Sirisena's office said in a statement.

Mendis also said security authorities failed to arrest the terrorist, Zahran Hashim, who led the attacks despite mounting evidence against him.

Official sources said Hashim came to the attention of authorities following a clash with a moderate Muslim group in his village in eastern Sri Lanka two years ago.

Parliament on Wednesday began investigating the circumstances leading up to the attack on three churches and three luxury hotels.

Ten days before the attacks, police chief Pujith Jayasundara issued a warning that Hashim's National Thowheeth Jama'ath (NTJ) could target prominent churches. But this was not followed up.

The government has admitted there were intelligence failures before the attacks, in which 45 foreign nationals died and nearly 500 people were injured.

Mr Sirisena subsequently suspended Jayasundara and dismissed his top defence official.

Sri Lanka has been under a state of emergency since the attacks, but Mr Sirisena announced on Monday that it will end in a month.