After months in makeshift shelters, earthquake victim Bhim Bahadur Gurung is desperate to start rebuilding his house ahead of Nepal's biting winter, but a fuel blockade has left him unable to obtain vital construction supplies.

Nearly six months after a 7.8-magnitude quake killed almost 8,900 people and destroyed about half a million homes, thousands of survivors are still living in tents and other temporary shelters, dependent on aid.

But the three-week blockade of a major border checkpoint by protesters who reject Nepal's new constitution has sparked a fuel shortage and nationwide rationing, with vital supplies unable to get through.

"No cement, no rods, no roofs... how can I build my home?" 43-year-old farmer Gurung said from his village in Sindhupalchowk district, one of the areas worst hit by the devastating quake in April.

"The villagers are all living in temporary shelters right now, this won't be enough when it starts snowing," Gurung said.

Aid organisations say the fuel crisis has severely hampered their operations and the continued shortage could cut off relief supplies to communities in far-flung areas of the country.

The World Food Programme (WFP) said it had been forced to halt distribution of relief goods and shelter supplies to 224,000 quake victims because of the shortage.

"Because of the fuel crisis we've only been able to deliver 40 percent of the actual needs," said Seetashma Thapa, communications officer for WFP, which coordinates logistics for nearly 130 other humanitarian organisations.

"The situation is particularly critical as we are in a race against time to reach 84,000 people with vital food and supplies before the snow sets in," she said of those in the most remote areas.

The WFP's helicopter operations have only a week of fuel left, she said.

- 'Peak time' -

For three weeks, hundreds of protesters have blocked a bridge crossing in the town of Birgunj, 90 kilometres (55 miles) south of Kathmandu, through which 60 percent of the country's petroleum imports pass.

The protesters, from the ethnic Madhesi minority in Nepal's southern plains, are incensed about the planned division of the country into several federal provinces under the constitution introduced last month.

Slow movement at other checkpoints has prompted Nepal to accuse India, which has expressed concerns over the constitution, of imposing a blockade.

Landlocked Nepal is completely reliant on India for fuel supplies.

"We have been requesting the Indian Oil Corporation continuously to resume supplies, but the response has not been satisfactory," said Sushil Bhattarai, Acting Deputy General Manager of Nepal Oil Corporation.

"Right now we are only getting 10-15 percent of our regular imports," he said, adding that the state oil company has asked international fuel companies to supply petroleum products to Nepal.

Nepal's newly elected prime minister KP Sharma Oli has called on political parties representing the Madhesi community to halt their protests and hold talks.

But the parties have refused to come to the negotiating table, until the government submits a concrete plan to address their demands.

This weekend, Nepal's deputy prime minister and foreign minister flew to India to hold talks on getting the fuel and other critical supplies moving again.

India denies it is deliberately halting trucks at its border, insisting the disruptions are coming from the other side.

Govind Raj Pokharel, chief of the National Reconstruction Authority in the process of being set up by Nepal, said the blockade was also disrupting the production of materials required for reconstruction.

"Goods are stuck at the borders and strikes have forced factories to shut down. Even if they want to operate, their raw materials aren't coming in," Pokhrel said.

"This is the peak time for reconstruction. But this crisis will have a long-term impact on our recovery."

For victims like Gurung, the crisis translates to more immediate worries.

"The earthquake has troubled us enough, this fuel crisis is only adding to our pain," Gurung said.

"I pray that our government resolves this soon and pays attention to us before winter comes."