They join seven other candidates, including Mr Javid’s successor Nadhim Zahawi, Foreign Secretary Liz Truss, and Transport Secretary Grant Shapps, in vying for the top role with Mr Sunak.
The most significant absentee from the starting list so far is Penny Mordaunt, the trade minister who has been touted as one of the favorites for the job.
Conservatives organizing the contest are keen to whittle down the race to a final two before parliament goes on its summer recess on July 21. Over the next few days, barbs both political and personal will fly, and alliances will develop as candidates seek to shore up support from their fellow members of Parliament, who decide who goes through to the runoff.
In announcing his run in the Times newspaper, Mr Johnson loyalist Mr Shapps took a swipe at Mr Sunak, who resigned about the same time as Mr Javid on Tuesday (Wednesday AEST).
“I have not spent the last few turbulent years plotting or briefing against the prime minister,” Mr. Shapps told the paper. “I have not been mobilizing a leadership campaign behind his back.”
Mr Sunak declared his candidacy on Friday (Saturday AEST) in a slick video that raised eyebrows among Tory MPs who suggested plans had been in the works for longer than a few days.
And in what the Sun newspaper called the kind of dirty trick likely to sully the contest, a clip from 2007 resurfaced online showing Mr. Sunak making a dismissive comment about the working class.
Ms Truss will launch her bid by pledging that she will advocate “classic Conservative principles”, the Mail on Sunday reported. Mr Zahawi began his campaign with his own low-tax pledge and seemed to garner endorsements even before he announced, including from former Northern Ireland secretary Brandon Lewis.
Ms Truss ranked just behind Mr Sunak in an Opinion poll for Channel 4 News. He was backed by 25 percent and Ms. Truss by 21 percent in the survey of Conservative Party members, who will choose from the final two candidates.
In one of the more unexpected developments late on Saturday, a Times journalist tweeted that Tom Tugendhat, the centrist chairman of the House of Commons foreign affairs committee who was often critical of Mr. Johnson, won the endorsement of Anne-Marie Trevelyan, the international trade secretary and a key member of the right-wing European Research Group .
The other two declared candidates from outside Mr. Johnson’s cabinet are pro-Brexit Attorney-General Suella Braverman and Kemi Badenoch, minister of state for equalities.
Defense Secretary Ben Wallace, initially seen as a favorite to succeed Mr. Johnson, said at the weekend that he decided not to run.
Meanwhile, Mr. Johnson will stay on until his successor is announced, which the party said would be in September. He has appointed a caretaker government which he insists will not “make major changes of direction”.
The 1922 Committee of rank-and-file Tory MPs is drawing up plans for an accelerated leadership contest. The two finalists will then embark on a six-week tour of the UK, and more than 100,000 Conservative party members will decide who moves into 10 Downing Street.