Alfred Mutua's Maendeleo Chap Chap scored a major victory in Kilemi Mwiria's defection to the party from Jubilee.
Dr Mwiria was unveiled at the party headquarters in Nairobi yesterday as the contender for the governor's seat in Meru County.
This puts him in place for a head to head battle with his bitter rivals, Meru Governor Peter Munya and Senator Kiraitu Murungi in the August polls.
The defection sent shock waves in the Jubilee Party in Meru, with insiders such as South Imenti MP Kathuri Murungi saying it signalled more defections in the near future.
"This confirms our often stated genuine concerns about the need to fix the flawed interim party branch elections held in December. More defections are looming if the party headquarters continue to ignore two petitions filed after the sham elections," said Mr Murungi.
The MP said he was waiting for party headquarters' reaction to a list of grievances before stating his political stand.
"While the presidential vote in Meru is likely to remain predominantly Jubilee, the party should be warned that no other seat is safe from being grabbed by friendly parties," he said.
But some Jubilee leaders described Mwiria's defection as a blessing for the party.
Igembe South MP Mithika Linturi said the political arithmetic in the governor's race would be easier for Jubilee with Mwiria's exit.
"The earlier they leave, the better," said Mr Linturi.