Cabinet Secretary Simon Case will appear before MPs following a string of explosive allegations made by Dominic Cummings.
She also failed to answer when a new independent adviser on ministerial standards would be appointed, but said the role would be filled "shortly".
Defence Secretary Ben Wallace on Monday declined to confirm or deny if Johnson had been given an undeclared loan from political donors to pay for the renovation of the flat.
While visiting Wrexham on Monday, Mr Johnson did not deny discussing using donors to fund the work.
Asked about this, he said: "If there's anything to be said about that, any declaration to be made, that will, of course, be made in due course". What mattered now was that Johnson had borne the cost himself, Wallace said.
A Downing Street spokesman said that the "costs of wider refurbishment have been met by the Prime Minister personally", adding: "Gifts and benefits received in a ministerial capacity are, and will continue to be, declared in transparency returns".
ITV political editor Robert Peston reported two "ear-witnesses" as saying that the comment was heard through an open door as Mr Johnson raged in his private study following the meeting which approved the second lockdown - suggesting that Mr Gove may not have been present at the key moment.
"The Prime Minister must now come to Parliament to give a statement, and face questioning, on these shocking claims and the growing Tory sleaze scandal engulfing Westminster".
'Let's not forget, while we are getting into Oscar-type gossip columns - there is an very bad lot of gossip going around.
"The Prime Minister has been utterly focused on delivering, alongside Cabinet colleagues, the response to Covid".
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The aunt said the teen had called police as well as some relatives for help, and then armed herself with a knife for protection. Ginther added, "BCI is on the scene conducting an independent investigation as they do with all CPD-involved shootings ".
Labour's Rachel Reeves urged Mr Johnson to apologise. Last week, the government accused Cummings of being the so-called chatty rat responsible for multiple leaks, notably the one that indicated that the government was planning for another lockdown on October 30, 2020.
"All the details will be given out in line with the rules", Ms Truss added.
Over the weekend, ministers had said the prime minister "personally paid the bill" for the flat but did not answer questions on whether a Tory party donor initially provided the money to him.
One former minister told MailOnline of the latest claims: 'This needs to stop because it is damaging both sides.
'It is also time for Carrie Symonds to back off, because it is clear in all of this that her name comes up regularly in the issues that are causing the PM difficulty - whether it is appointments, personnel, or having the flat redecorated'.
However, the Electoral Commission said that a month after it first revealed that it had contacted the Tory Party over a reported £58,000 donation in relation to the flat, those talks were still continuing.
Labour called for a full investigation.
On Friday, Mr Cummings said Mr Johnson wanted "donors to secretly pay for the renovation" - which he said was "unethical, foolish, possibly illegal and nearly certainly broke the rules".
She said: "As I said, he is covering the costs and it's being complied with fully".
Two cabinet ministers, defence secretary Ben Wallace and global trade secretary Liz Truss, have now gone on the record as saying Johnson paid for the work out of his own pocket.