UN High Commissioner for Refugees goodwill ambassador Angelina Jolie listens to an earthquake survivor during her visit to Jabel Sharoon. Picture / Reuters

UN High Commissioner for Refugees goodwill ambassador Angelina Jolie listens to an earthquake survivor during her visit to Jabel Sharoon. Picture / Reuters

ISLAMABAD - Hollywood actress Angelina Jolie said promises of help for Pakistan's earthquake survivors must be kept, and quickly, or many people could freeze to death as a bitter Himalayan winter grips the region.

Jolie, a goodwill ambassador for the UN refugee agency, visited a remote valley laid waste by the October 8 earthquake that killed more than 73,000 people, most of them in the mountains of northern Pakistan.

"There's another disaster that could happen very soon," Jolie told a news conference in the capital, Islamabad, which she attended with UN High Commissioner for Refugees, Antonio Guterres.

Aid donors have promised Pakistan about $6 billion in help but most of that is for medium- and long-term reconstruction.

Jolie, on her third visit to Pakistan, said quake survivors needed help now.

"There's so many wonderful pledges of money that could come in the next few years, but this winter is in the next few weeks," she said.

"So many people are in danger of possibly freezing to death."

Hundreds of thousands of quake survivors are still in need of emergency food and shelters, seven weeks after the disaster.

Aid officials warn of sickness sweeping through a cold and poorly nourished population, causing a second wave of death unless people get the help they need before the snow comes.

The United Nations said it had received $216 million for short-term emergency relief, or 39 per cent of the amount it had appealed for, and said it urgently needed the rest before winter.

"The race to provide suitable shelter in time is not lost yet, but the consequences of failure, resulting from the lack of relief funds, could result in the deaths of vulnerable people," said UN relief official Jan Vandemoortele.

Oscar-winning Jolie has travelled widely for the Nobel-winning UN agency, which protects people fleeing wars and persecution, including Sierra Leone, Cambodia, Kosovo, Russia and Sudan's Darfur region.

She arrived in Pakistan last week with actor Brad Pitt, with whom she has been romantically linked. Pitt did not attend the news conference.

Asked about her impressions on her trip to the disaster zone, Jolie said the scale of the devastation was colossal.

"It's a huge situation ... nobody sitting at home has any idea what this really looks like. It's unbelievable," she said.