Sri Lankan government troops have seized a strategic village from separatist Tamil Tiger fighters, bringing the government closer to capturing the rebels' de facto capital in the north of the country, the military has said.

The battle for Vannerikulam village, west of the rebels' capital, Kilinochchi, was challenging because the rebels had erected massive earth barriers, the military said in a statement on Monday.

It said the capture of the village on Sunday could ease the military's march towards Kilinochchi, which has housed the rebel headquarters for the past 10 years.

The military did not release any details on casualties from the battle, and it was not possible to contact rebel officials for comment because communication lines to the territory had been severed.

Government troops have made dramatic progress on the northern fronts in the past months, seizing a series of rebel bases and chunks of land.

Stiff resistance

But the rebels have offered stiff resistance as government troops approach the edge of Kilinochchi, 330km north of Colombo, the Sri Lankan capital.

The government earlier this month said it was poised to capture Kilinochchi.

That drive, however, could take longer than anticipated with the rebels digging in, analysts and military sources say.

"Troops operating in the south of Kilinochchi are making progress, though they have not shown a rapid progress within the past few days," Ranil Wijayapala, a defence analyst writing in the state-run Daily News, said.

"With the rapid advance last month, the military is also forced to tie down a lot of soldiers to protect areas newly captured from the Tigers," a military officer, who declined to be named, said.

"The Tigers won't be able to hold Kilinochchi for too long, but they can delay the fall."

The government has vowed to crush the rebels and end their 25-year campaign for a separate homeland for the island's ethnic minority Tamils, who have suffered marginalisation by successive governments controlled by majority ethnic Sinhalese.

More than 70,000 people have been killed in the conflict so far.