Sri Lanka's president has promised to free jailed former army chief Sarath Fonseka unconditionally and at the earliest opportunity, the ex-general's wife said on Thursday.

Pakistan coach Dav Whatmore on Wednesday warned his players they faced a battle on next month's tour of Sri Lanka, saying the hosts were tough opponents in home conditions.

Sarath Fonseka could be free "within days" after Sri Lankan President Mahinda Rajapakse held talks on Wednesday with the jailed former army chief's political party, officials said.

Sri Lankan sailors march during a Victory Day parade rehearsal in Colombo.

Sri Lankan authorities are mulling a pardon for jailed former army chief and defeated presidential candidate Sarath Fonseka amid international calls for his release, an official said Tuesday.

Sri Lankan security forces said they have uncovered a huge haul of weapons hidden by separatist Tamil Tiger rebels before they were crushed three years ago, including enough explosives to "blow up a town".

Sri Lankan authorities released information for the first time on Sunday about thousands of people held under draconian anti-terror laws despite it being three years since Tamil rebels were crushed.