Hundreds of thousands of quake victims in Nepal are unable to start rebuilding their homes as winter approaches because a $4.1 billion reconstruction fund cannot be spent until lawmakers pass a long-delayed bill -- to the frustration of international donors.

Five months after a devastating quake that killed nearly 9,000 people and destroyed around half a million homes, many people have received little aid beyond an initial $150-per-household government payout.

Victims who lost their homes were promised $2,000 in compensation, but the man in charge of disbursing those funds says his hands are tied until MPs pass a bill conferring legal status on the new National Reconstruction Authority (NRA) that he heads.

That looks unlikely to happen any time soon.

The Authority's newly-appointed chief executive Govind Raj Pokharel said that even if there were no further hold-ups, it would be several weeks before the bill could be passed.

"If there is still no consensus (on the bill) it might take even more time. We are finalising housing building codes, that is at the final stage... But we don't have the legal authority to disperse money," he told AFP.

"It is really painful to see people suffering on the one hand, and to know on the other that there is $4.1 billion that could help them."

International donors who pledged billions of dollars towards rebuilding the desperately poor country at a major conference in June are growing increasingly frustrated by the failure to formally establish the NRA, which will process all aid funds.

This week they urged the government and parliament to complete the necessary legislation "as a matter of urgency" to provide much-needed support to vulnerable people.

The Authority was "crucial to effectively oversee the huge reconstruction tasks", said the statement from the International Development Partner Group, made up of donor countries and UN and other agencies.

- 'Government has done nothing' -

Meanwhile, homeless Nepalis have been unable to buy the materials they need to start rebuilding as the monsoon rains draw to an end.

Thousands are still living under flimsy tarpaulin shelters as the winter approaches.

They include Surya Ram Jwanabasa Pharma and his family who set up camp on a local football pitch using tarpaulins donated by a charity after their house collapsed in the quake.

"The government has done nothing for us," said the 44-year-old as he looked out over the waterlogged camp in the historic town of Bhaktapur.

"If I could at least build a shed, I wouldn't have to live like this. All I need is around 30,000 rupees ($300) to buy tin so I can build a basic shelter for my family."

Another resident Dila Maya Dhoju recalled how her daughter-in-law, who had given birth just days earlier, had to wade through waist-deep water to take her new baby to higher ground when the river engulfed the camp during the monsoon rains.

When she returned, all her possessions had been washed away.

But even this desperate situation could get worse -- community leaders have told Pharma he cannot remain on the football pitch and must find somewhere else to go.

"We were 166 families here at first," he told AFP.

"People who had a choice have moved on already. But people like us who have nowhere else to go, we have to stay."

Just a few miles (kilometres) away in Kathmandu, the focus is on a new national constitution that has sparked deadly protests and a diplomatic row with India.

Lawmakers agreed Saturday to end the current session of parliament after approving the bill following years of disagreement over its contents.

The charter's adoption will trigger a change in government that some fear could further delay the formal establishment of the NRA.

One senior diplomat in Kathmandu told AFP there were concerns a new government might seek to replace Pokharel, a former vice-chairman of the national planning commission who was only appointed last month.

"We are losing precious time," said the diplomat, who spoke on condition of anonymity.

"To be honest, none of the international partners engaged in the reconstruction effort are happy about the way things are going.

"He (Pokharel) gained our confidence. If he's suddenly pushed aside, we won't be very happy."