Raila Odinga said there was enough evidence to investigate the ministers
Kenyan Prime Minister Raila Odinga will ask former UN chief Kofi Annan to intervene in an increasingly bitter power struggle, his office has said.
Mr Odinga is at loggerheads with President Mwai Kibaki over who has power over cabinet affairs.
On Sunday, the prime minister suspended two ministers suspected of corruption - only for Mr Kibaki to overrule him.
The BBC's Will Ross in Nairobi says many Kenyans have been left wondering who is in charge of the country.
He says people fear that the wrangling will end any hope of winning the fight against corruption, and many Kenyans have lost faith in all politicians.
School money stolen
Mr Kibaki and Mr Odinga - bitter political rivals - joined together in a unity government to end violence that swept the nation after the 2007 election.
But now, both men have accused each other of overstepping their constitutional remit.
"The legal provisions on which the prime minister acted, do not confer him the authority to cause a minister to vacate his or her office," the president's office said in a statement.
But Mr Odinga told the BBC's Network Africa programme he had not sacked the ministers, he had merely suspended them - which he was entitled to do.
"I think that what I've done actually has been within my constitutional powers, and that the president does not have the powers to countermand what I have done," he said.
Mr Odinga's office now say they will ask Mr Annan to intervene.
The former UN secretary general mediated the power-sharing agreement between Mr Kibaki and Mr Odinga.
The two ministers at the centre of the spat - Agriculture Minister William Ruto and Education Minister Sam Ongeri - both turned up for work on Monday and say only the president has the power to discipline them.
A recent audit into a maize scandal revealed that $26m (£16.5m) had gone missing.
And more than $1m was stolen in an education scam.
Mr Odinga said there was enough evidence implicating the two ministers for an investigation, so they should be suspended.