As part of a landmark peace deal ending a decade of bloody civil war late last year, the fighters have been confined to UN-monitored camps.

But the camps have no clean water and inmates run the risk of disease, the Maoists say.

"We'll start a nationwide strike and peaceful protests from Sunday if the government fails to make a decision to improve camp conditions," Maoist leader Prachanda said on Saturday, according to state-owned Nepal Television.

"Most of our fighters are living in inhuman camp conditions," Prachanda told reporters in Pokhara, 140 kilometres (87 miles) west of Kathmandu.

Management of the camps is the responsibility of the government but "it (the government) has not been serious enough in tackling the issue," he said.

Some 31,150 Maoist fighters are in the camps.

"Most of our fighters are living in straw and plastic-covered shelters. There is no electricity or clean water," Nanda Kishor Pun, Maoist deputy commander and vice chairman of the joint arms management committee told AFP.

"When there is strong wind and rain it becomes impossible to stay," he said. "We want the government to address our problems right away as the conditions will only worsen because of the fast-approaching monsoon."

The ultra leftists launched their "People's War" in western Nepal in 1996. However, they now say they have renounced violence and will work within a democratic system.

Since making peace, the former insurgents have been given five ministerial portfolios in the government.

At least 13,000 people had been killed in the conflict by the time the government and Maoists signed the peace deal last year.