The Nationalist Party MPs who sit on the Public Accounts Committee have formally asked Police Commissioner Angelo Gafa to investigate allegations of false testimony, following what Keith Schembri said during Tuesday's committee meeting.

During the meeting, "Keith Schembri, who was testifying under oath, alleged that both Edward Scicluna, the former finance minister who is currently the Governor of the Central Bank, as well as the former Deputy Police Commissioner Silvio Valletta, lied under oath while testifying before the public inquiry into the assassination of journalist Daphne Caruana Galizia," PN Graham Bencini said in a Facebook post.

"Because there is a person, or persons, who gave false testimony under oath, as the three PN MPs on the Public Accounts Committee we filed a formal request to Commissioner Angelo Gafa to investigate this allegation of false testimony, and to take all the opportune steps in these circumstances," he added.

The three PN MPs were Graham Bencini, David Agius and Darren Carabott (who is the PAC chairman).

Darren Carabott said on Facebook their either Scicluna, Valletta, or Keith Schembri, who was the chief of staff to former Prime Minister Joseph Muscat, "isn't saying the truth, even though they took an oath saying that they were."

"False testimony under oath is a criminal act," he said.

During his testimony on Tuesday, Schembri was asked about former Finance Minister Edward Scicluna's 'kitchen cabinet' statement. Among other things, Schembri said that Scicluna would have been involved in major decisions, and also said that there was no kitchen cabinet.

Schembri was asked about testimony given by former Deputy Police Commissioner Silvio Valletta during the public inquiry into the assassination of journalist Daphne Caruana Galizia. PAC Chairman Darren Carabott read: "he told the board that Keith Schembri, the Chief of staff of the Prime Minister had called him and told him 'You're going to go and talk to Yorgen Fenech because a report simply appeared in the Times?'" Schembri said he didn't make that comment. He said he did not try to tell Valletta not to go and talk to Yorgen Fenech.