The former Fiji prime minister, Sitiveni Rabuka, says Laisenia Qarase and Mahendra Chaudhry must work together or face being called liars.
Mr Rabuka spoke on Fiji TV after Mr Qarase again said he could not work with Labour Party leader, Mahendra Chaudhry because of differences in their style and principles.
The Supreme Court has ordered Mr Qarase to form a multi-party cabinet which includes Labour without delay, adding that it is a command of the constitution which must be obeyed.
Mr Rabuka, who was instrumental in formulating the 1997 Constitution, says this is not the time to talk about differences but about how the multi-party cabinet should work .
He says both men have made committments to take Fiji forward, Mr Chaudhry on becoming prime minister in 1999 and Mr Qarase after the 2001 election.
Mr Rabuka says if that is their common ground, then all they have to work out is how they will achieve that.
He says otherwise they would be called liars.
A telephone poll conducted by Fiji Television last night found that 62 per cent of people thought the two men could work together while 38 per cent thought they could not.