Kenyan President Mwai Kibaki has opened parliament with a promise that his government will complete constitutional reform as soon as possible.
The row threatens the future of the ruling coalition
President Kibaki also urged national unity, describing the rewriting of the constitution as democratic renewal.
But the draft constitution - which would reduce the president's powers and create an executive prime minister - has split the ruling coalition.
Mr Kibaki has spent days in discussions with MPs to try to find a consensus.
The governing coalition has split along party and largely ethnic lines, with those closest to Mr Kibaki keen to retain a strong presidency.
"Let us avoid portraying our country as a quarrelling nation because of personalisation of issues and short-sightedness," Mr Kibaki told MPs.
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Mr Kibaki said the government would proceed with legislation which would enable MPs to amend the draft constitution before agreeing on it.
Parliament is expected to debate two bills this week, that if passed would give it powers to amend the draft - approved by a constitutional conference.
However, the opposition in parliament have said they will side with Mr Kibaki's opponents - which would give them a majority opposed to the bills.
The country's High Court has temporarily barred any further debate on the constitution at present.
But it is unclear if MPs will adhere to this ruling, which has preoccupied them since the conference ended two weeks ago.
At the constitution conference, most of the 629 delegates - including three cabinet ministers - voted to trim presidential powers against the government's wishes, proposing the creation of a prime minister's post after the next elections in 2007.
The government has repeatedly promised that the country's 40-year old constitution, which dates back to independence from Britain, will be replaced by June.
But the BBC's Grant Ferrett in Nairobi says the disagreements over the draft document are so intense that the target date is unlikely to be met.