Defeated Sri Lankan presidential candidate Sarath Fonseka – currently detained in military custody – is to stand in April’s parliamentary polls.
Party sources told the BBC that he would lead a new opposition alliance.
Sri Lanka’s authorities have meanwhile announced a raft of possible civilian charges against Gen Fonseka in addition to any military cases against him.
Earlier this week he argued he should not face military charges because he had retired from being a general.
But the government argues he is subject to military law for up to six months after quitting the army.
The authorities accuse Gen Fonseka of having worked with what they call anti-government forces, but no specific military charges against him have been brought.
Correspondents say that the move to file civilian charges against him – including allegations that he allowed his son-in-law to profit from an arms deal – shows the determination of the authorities to keep the general incarcerated either by military or by civilian law.
On Thursday, the general signed nomination papers to contest a seat in Colombo, representing the Democratic National Alliance – comprising six parties – in April’s polls.
The opposition is weaker than it was during January’s presidential polls, because the coalition that supported his presidential candidacy has split up into several blocs.
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