His campaign says Rishi Shank has secured the 100 MP nominations needed to enter the race to become the next Conservative leader and prime minister.
The former chancellor has yet to announce whether he will launch a fresh bid for the top job after losing out to Liz Truss in the summer.
Boris Johnson is heading back to Britain as supporters rally behind a possible return of the former prime minister.
Penny Mordaunt is the only contender to have officially launched a campaign.
Hopefuls have until 14:00 BST on Monday to find 100 backers. If a candidate reaches 158 nominations, the race will be reduced to two candidates, as there will not be enough MPs left to support a third candidate.
It will then go to an online ballot for Conservative Party membership, with the results to be announced on Friday.
But, if Conservative MPs choose a single candidate, we could have a new prime minister by Monday afternoon.
Polling suggests Mr Johnson – who was ousted by his own MPs three months ago – will be favorite to win the members’ vote.
He has 44 declared backers so far, according to a running total kept by JEE News, although other sources suggest it could be higher.
Mount Johnson is due to land back in the UK after a Caribbean holiday, when his supporters hope he will announce a campaign to return to Downing Street.
A close ally, Sir James Duddridge, said he had received a message from the former prime minister saying: “I’m coming back, Dudders. We’re going to do it. I’m up for it. “
His supporters say he is the only contender to win the support of the voting public after winning the 2019 general elections. Mr Johnson still faces a parliamentary inquiry into whether he lied to MPs about Partygate.
Mr Sink has the support of a number of senior colleagues, including former chancellor and health secretary Sajid Javed, security minister Tom Tugendhut and former health secretary Matt Hancock.
“It is abundantly clear that Rishi Shank has what it takes to meet the challenges we face – he is the right person to lead our party and take the country forward,” Mr Javed said.
Another supporter, Tobias Ellwood, said he was the 100th MP to endorse Mr Sink, adding: “It is time for a centralised, stable, fiscally responsible government with credible domestic and international leadership. Offer.”
Mr Sink currently has 97 backers, according to the JEE News tally of MPs on record with support.
House of Commons leader Penny Mordant, who came third in the last leadership election, has 21 supporters, according to JEE News. More than half of the parliamentary parties have yet to say which way they will vote.
Launching her campaign on Twitter on Friday, Ms Mordant said she would “unite our country, keep our promises and win the next [general election]”.
Mordaunt’s backer Conservative MP Bob Seeley said “I think we have a collective responsibility as a country to apologise” and said he believed Ms Mordaunt had the ability to provide “unity and leadership” within the party. It is the best opportunity.
Among those who have ruled themselves out of the running are Defense Secretary Ben Wallace – who has said he is “leaning” towards backing Mr Johnson – and current chancellor Jeremy Hunt.
