Theresa May is set to be called by MPs to explain whether the Home Office covered up allegations about the conduct of the former child sexual abuse inquiry chair, Dame Lowell Goddard.

The home affairs select committee announced that it is considering calling the prime minister after summoning the permanent secretary to the Home Office, Mark Sedwill. This follows the admission on Saturday by his department that it had been aware of concerns about Lowell’s conduct before she resigned on 4 August.

When home secretary Amber Rudd gave evidence to the select committee on 7 September, she told MPs that “all the information” she had was that Lowell had quit because she was “a long way from home” and “too lonely”.

The New Zealander has been accused of using racist language to colleagues at the child abuse inquiry, allegations she has described as “falsities”, “malicious” and part of a “vicious campaign”.

Conservative MP Tim Loughton, the acting chair of the select committee, said Sedwill would give evidence “on the basis that he was sitting alongside the new home secretary [Rudd] when the committee questioned her about the Lowell Goddard situation.

“The committee will then decide whether to call May, rather than Rudd, as she was home secretary when the whole thing came to a head about Lowell Goddard,” Loughton said. “This isn’t something that has just happened in the last couple of months, this is something that started happening last year.”

Loughton said Sedwill “must have been aware” of concerns coming out of the inquiry, adding: “Forty Home Office staff are seconded to the inquiry and I would be very surprised if the permanent secretary didn’t make his then home secretary aware that there were rumblings about the chair.”

Shadow home secretary Diane Abbott said: “These are grave allegations and the home secretary and prime minister must address them urgently.

“Despite being given every reason not to trust the establishment, the victims of child sex abuse had put their faith in this inquiry. We cannot afford to lose their trust again.

“We must be given an assurance that there was no attempt to cover up the accusations made about Judge Goddard. Because, if true, it would mean that the home secretary knowingly put at risk the integrity of the entire inquiry.”

Lowell’s replacement, Professor Alexis Jay, is due to give an update on Monday on the progress of an internal review of the inquiry’s approach to its investigations. Jay will also appear before the select committee.