Norway's deputy foreign minister Vidar Helgesen said the rebels needed to be given time to transform themselves into a political group before a permanent settlement could take hold.
"It takes time to train hundreds, if not thousands, of guerrillas in political thinking. It is of vital importance that the other side realise the importance of allowing time to build political capacity," he said at a public lecture in Colombo.
The sixth round of talks, beginning in Japan on Tuesday, were nearly scuttled after the navy sank a rebel boat it suspected of smuggling weapons, killing all 11 on board, but both sides have confirmed they will remain at the table.
Helgesen said questions of how better to implement the ceasefire agreement, which has been holding since February last year after the conflict that killed 64,000, would be a focus at the talks.
"There is a lot to be said about the quality of the implementation of the ceasefire, not least over the last few weeks. There is a need to focus on that implementation," he said.
The sea clash was the most serious incident since the ethnic minority separatist rebels and the government agreed on a ceasefire.
In Sri Lanka's eastern port city of Trincomalee, shops, offices and schools were closed on Friday in a protest against the clash.
"The town is pretty empty. The Tamil Tigers have organised this," said one resident, who declined to be identified.
Helgesen said he believed the strategy of implementing elements of a peace plan, such as commitments on rebuilding war-torn areas, and on human rights, would lead to a more durable final settlement.
"What I think is a very good feature of this process, is that the negotiations and the implementation are taking place at the same time," he said. "It doesn't make the road shorter, but it does make the end clearer."
- Reuters - Thomson Reuters Foundation
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