According to Sky News, passing the 100-vote threshold means that Johnson will likely be on the leadership ballot.
Earlier in the day, Johnson reportedly returned to the country amid speculation that he might attempt to vie for Conservative leadership after the resignation of Liz Truss.
His contender, former UK Finance Minister Rishi Sunak, hit 100 Conservative supporters on Friday, Sky News reported, citing a source within Sunak's campaign.
Truss stepped down on Thursday, becoming the shortest-serving PM in British history. As the leadership race started, Boris Johnson returned to the country from the Caribbean, sparkling reports about his plans to run for prime minister once again.
Britain's Prime Minister Liz Truss delivers her keynote address on the final day of the annual Conservative Party Conference in Birmingham, central England, on October 5, 2022
© AFP 2023 / PAUL ELLIS
To elect a new Tory leader - and thus a new PM - the Conservatives will hold an online poll with the ballot closing on October 28. While Johnson is yet to announce his decision on running for office, ex-Chancellor Rishi Sunak, Commons leader Penny Mordaunt and Trade Secretary Kemi Badenoch have announced their bids for the premiership.