Harriet Harman, a senior Labour MP, will lead an inquiry into the possibility that Boris Johnson misled Parliament in relation to No 10 parties during lockdowns.
After meeting on Wednesday, the cross-party Privileges Committee was made up seven MPs and issued a call to evidence.
It stated that it would seek "witness information" and evidence, and that hearings would commence in the autumn.
Johnson denied that he knew he had given the Commons false information. He said it was "what i believed to be true".
The committee stated that it is open to receiving evidence anonymously from anyone provided their identity can also be verified.
The information could include evidence that Mr Johnson knew about the activities at 10 Downing Street, and the Cabinet Office, under Covid regulations, starting from the occurrence thereof, and any briefing or inquiry made by Mr Johnson in relation to these events.
Sir Ernest Ryder, an ex-appeal court judge, was appointed adviser to the committee.
In December 2021, he conducted an audit into the fairness of the House of Commons standard system.
The MPs approved the launch of this new inquiry in April. However, they stipulated that it should only be launched after the investigations by the Metropolitan Police are complete.
In May, the police investigation concluded with 126 fines, including penalties for Carrie, the prime minister, and Rishi Sunak, his Chancellor.
Sue Gray, a senior civil servant, reported that there were "failures in leadership and judgment at No 10", for which the "senior leadership at the centre, both official and political, must take responsibility."
Johnson claimed that MPs had not broken Downing Street rules when the first reports of lockdown parties emerged. Opposition politicians, however, have accused Johnson of lying.
When asked last year about a No10 party on 18/12/2021, he said that all guidance was being followed in No 10.
He stated that he had been repeatedly assured that there was no party, and that no Covid rules were violated on 8 December 2021.
Ministers who intentionally mislead Parliament are required to resign.
When asked about April's inquiry by the committee, Johnson stated that he had "absolutely everything, frankly," to hide.
After hearing evidence, The Privileges committee will issue a report that will state whether it believes Johnson misled Parliament.
If it discovers that he did it, it can recommend a sanction. This could include suspension or expulsion completely from Parliament.
It could also suggest that he apologizes to the House.
The report will be approved by the MPs and the sanctions implemented.
The Privileges Committee consists of seven MPs: two Labour MPs and one SNP MP. It also includes four Conservatives.
The committee chair, Labour's Chris Bryant, resigned from the investigation because he had previously commented publicly on the subject.
The committee unanimously voted to replace Mr Bryant by Ms Harman, former deputy Labour leader.
Separately, the ex-head of the government's Covid taskforce was issued a fixed penalty notice after she attended a drinks event to mark the end of her civil service career. She is now to continue her role as chief executive at Sheffield City Council.
Kate Josephs has apologized for the second time and received a written warning form from the council.
