More people were saved from under the debris in Haiti on Friday, but lack of medications could threaten the lives of those who were severely injured, rescuers said.

As clock is ticking near the critical 72-hour mark after the 7.3-magnitude temblor on Tuesday, aid workers have revved up efforts to search for any sign of lives.

"During late Thursday night and early Friday morning, the Chilean rescue team collaborated on retrieving 23 people alive" at the Montana Hotel, said chief of the Chilean aid commission, Juan Gabriel Valdes.

Valdes said rescue efforts at that spot would continue as there were hopes of finding more people alive there.

Several senior officials who were injured when the government buildings collapsed in the quake have been brought to hospitals in neighboring Dominican Republic.

Minister of Public Works Joseph Frentz, whose left leg was broken, has been under intensive care at a Dominican Republic hospital, according to media reports.

President of the Haitian Senate, Kelly Bestien, was also taken to a hospital in Santo Domingo, after being injured when the Senate building caved in around him. He has already got a surgery in his leg and is recovering.

Most hospitals in capital Port-au-Prince are paralyzed with a lack of staff and minimum medical supplies.

There are shortages for practically everything -- drinking water, electricity, medicines, basic equipment and even fuel for ambulances, said Gu Laroche, director of the General Hospital.

Cuban aid workers have taken charge of the De la Paz Hospital, since its doctors have not appeared after the quake.

They complained of a lack of anaesthetica, serum, plaster, and orthopedic materials to conduct amputations or fix the broken bones.

The injured were dying at the hospitals, they said.

Meanwhile, many Haitians waited in a line to be treated by the Chinese doctors on the plaza in front of the building used to be the prime minister's office.

"Doctors and medicine are of great need here (..) I hope more rescue teams join us," said Hou Shike, a doctor with the Chinese rescue team.

The quake has dealt a hard blow to the small Caribbean nation. UN statistics shows that 70 percent of Haiti's population live in poverty and half of its 8.9 million people are unemployed.

The Food and Agriculture Organization has designated Haiti as one of the world's most economically vulnerable countries.

The United Nations and its partners Friday appealed for 562 million U.S. dollars to help the quake victims, as the world body has scaled up its assistance in the wake of the disaster.

The sum of 562 million U.S. dollars is intended to assist an estimated 3 million affected people over a period of six months, with half of the funds being earmarked for emergency food aid, and the rest to be used for health, water, sanitation, nutrition, early recovery, emergency education and other needs.

According to the Haitian civil protection ministry, more than 50,000 people were estimated to have died in the quake, with the number possibly closer to 100,000.

UN Secretary-General Ban Ki-moon said Thursday that it would take days to get the death toll, but the figure could be "very high."

Aid workers and assistance cargoes continued to arrive in Haiti on Friday, but many of the capital's 3 million people are without access to food, water, shelter and electricity.

The quake not only toppled the government buildings, but also shattered its fragile public service system, with many officials injured and more unaccounted for. This has made it hard to coordinate the distribution of the relief material.

The relief effort has also been challenged by the destruction, Ban said on Friday, citing blocked roads and limited capacity at the capital's one-runway airport.

"Although it is inevitably slower and more difficult than any of us would wish, we are mobilizing all resources as fast as we possibly can," said the UN chief.