Opposition leader Ranil Wickremesinghe met President Mahinda Rajapakse and urged him not to bring opposition lawmakers into the cabinet, a move the party has said would wreck the deal, but the request was turned down, a top official source said.

"The president made it clear that he was not fishing, but the opposition MPs were stalking him and were ready to cross over en masse," said the source close to Tuesday's talks at the presidential secretariat.

Rajapakse's leftist Sri Lanka Freedom Party and the right-wing United National Party (UNP) in October agreed to work together to hammer out a political solution to the long-running Tamil separatist conflict.

UNP spokesman Jayalath Jayawardena told AFP the October deal would be formally annulled if the government accepted any more defectors from the opposition to the cabinet.

"From the minute the cross-overs are accepted to the cabinet, our memorandum of understanding will cease to exist," Jayawardena said, adding that it would be a further blow to the already faltering peace efforts.

Sri Lanka's key international backers, including the US, European Union and Japan, had wanted the two main majority Sinhalese parties in the island to build on their October deal to offer a consensus plan to Tiger rebels.

Neighbouring India too had asked Sri Lanka's leaders to consolidate the deal and resume negotiations with the Tamil Tigers in line with a Norwegian-backed peace initiative. The last round of peace talks in October ended in failure.

In the island's east, government forces stepped up an offensive against Tamil Tiger rebels and said at least 30 guerrillas were killed Tuesday for the loss of one soldier.

The defence ministry said warplanes were deployed to hit suspected Tiger targets, while the guerrillas set off a Claymore mine elsewhere and killed two constables.

The Liberation Tigers of Tamil Eelam (LTTE) dismissed the ministry claims and said they had beaten back an army ground offensive, placing their casualties at seven cadres wounded during a five-hour battle.

In Colombo, political sources said at least 18 opposition legislators were to be rewarded with ministerial positions shortly in a move that will strengthen the ruling party's hold on the legislature.

President Rajapakse said in October his deal with the opposition was a solid backdrop to find a political way out of ethnic violence which has claimed more than 60,000 lives in the past 35 years.

Last week, the president discounted local reports that he would call a snap parliamentary election, but said a cabinet reshuffle was being considered.

Rajapakse came to power in November 2005 and inherited a parliament elected separately in 2004 where his own party is in the minority and depends on radical Marxists and Buddhist monks for survival.

Political analysts have speculated that the president may be tempted to go for an early poll, four years ahead of schedule, to build on his own popularity and boost his hold on parliament.

The Marxists, who initially supported him, have withdrawn their backing following disagreements over the handling of the peace process with Tamil Tiger rebels which has all but collapsed.

The Marxists and a party of Buddhist monks oppose any concessions to the Tamil Tigers.