About 100 Taliban militants are dead after two separate clashes in southern Afghanistan's violent Helmand province, officials said Sunday.

In the first skirmish, Taliban fighters unleashed a surprise attack on Afghan soldiers outside of Lashkar Gah, the provincial capital, according to Daud Ahmadi, the spokesman for Helmand's governor.

The militants bombarded the city with rocket fire from three sides shortly after midnight before NATO air strikes pushed back the fighters, Ahmadi said.

NATO aircraft bombed the insurgents after observing them gathering for the attack, a NATO statement said.

"If the insurgents planned a spectacular attack prior to the winter, this was a spectacular failure," Brig. Gen. Richard Blanchette, the spokesman for the NATO-led force, said in a statement.

British forces are primarily responsible for security in Lashkar Gah and surrounding areas.

When the fighting was over, officials rounded up the bodies of 41 militants from the city's outskirts while the fighters themselves may have gathered another 20 bodies, Ahmadi said.

No civilian casualties were reported.

During the second battle in Helmand province, Afghan and international forces recaptured the district of Nad Ali, which had been held by Taliban militants.

About 40 Taliban insurgents died in the three-day fight, Ahmadi said. However, he reported no casualties among Afghan or NATO troops.

The bustling drug trade in Helmand province is a source of consternation for international forces stationed in Afghanistan.

The region is among the world's largest drug producers and accounts for more than half of Afghanistan's poppy production.

The country produces more than 90 per cent of the world's opium, which is the main ingredient in heroin.

It is suspected that nearly US$100 million in proceeds from the poppy trade funds the Taliban insurgency.

With files from The Associated Press