WASHINGTON — A House committee hearing on Tuesday about the new Consumer Financial Protection Bureau disintegrated into heated accusations of lying, with the panel’s chairman accusing Elizabeth Warren of giving misleading testimony at a hearing in March and of making up facts about her agreement to testify this week.

Representative Patrick T. McHenry, a North Carolina Republican who is chairman of a subcommittee of the House oversight committee, told Ms. Warren, who is directing the start of the consumer agency, that he believed she had misled Congress about her role in settlement talks between government authorities and mortgage servicing companies.

Ms. Warren denied Mr. McHenry’s accusation, saying that she clearly stated in March that she had provided advice to officials of the Treasury and Justice Departments about their investigations of fraud among mortgage-servicing companies and about their settlement discussions with the companies.

The argument was a rare collapse of the decorum that usually pervades discussions among even the most fervent opponents on Capitol Hill. It demonstrated the level of frustration some Republicans apparently have over the consumer agency, its leadership and its authority as established by the Dodd-Frank Act that followed the financial and mortgage crisis.