The estimated cost of rebuilding after the tremor, in which 31,000 people died and about 22,000 were injured last month, was contained in a document given by UN humanitarian officials to representatives of about 48 countries at a meeting here.

"At present, initial estimates indicate that the long-term recovery could cost anywhere between 700 million dollars to one billion," (550-785 million euros) the document said.

Most of that amount over the next two years is likely to be garnered by the Iranian authorities, but the international community should provide "critical support", the UN document said.

"The reconstruction is, according to the estimates, likely to last about two years and will certainly cost 700 million dollars," said Elizabeth Byrs, spokeswoman for the UN Office for the Coordination of Humanitarian Affairs (OCHA).

"That's a minimum estimate," she added.

The UN also gave donors a detailed rundown on its needs over the next 90 days after it appealed for an extra 73 million dollars in aid with the international Red Cross on Thursday.

"This appeal will try to gently bind the first emergency rescue effort with the work and planning needed for reconstruction," Byrs said.

"There will be more appeals in the medium- and long-term," she told AFP.

Australia was the first country to come forward with a new donation of two million Australian dollars (1.52 million US dollars) for relief, UN officials said after the meeting.

The United States indicated it would take a positive outlook on the further relief effort, after it gave more than four million dollars of assistance in the emergency phase, they added.

"They said they would look into it very positively," said Jesper Lund, head of the UN disaster assistance team for Bam, who attended the meeting.

Part of the aid will go towards better shelter for families currently in tents, and building a hospital to replace the city's three hospitals which were destroyed.

The earthquake on December 26 killed about one-third to a half of Bam's health workers, the UN estimated.

Relief funds do not normally include assessment of damage to the cultural heritage, but the UN said it had decided to start a study with Iran on rebuilding the ancient city of Bam.

"In this particular case, the UN came to the conclusion that rehabiliation of the cultural heritage of Bam is an essential element for the restoration of the livelihood of the population," said Rashid Khalikov, a deputy-director of

A discussion was now underway in Iran about how it could be rebuilt, with modern building techniques likely to resist earthquakes in the area, which lies near a major geological fault line, he added.

So far about 100 million dollars in aid has been provided by 60 countries since the earthquake struck, Byrs said.

About 80 percent houses were destroyed or damaged in Bam and 75,000 people are homeless, the UN estimated.

Some 2,500 children orphaned in the earthquake were also receiving help, while many more children might need help to overcome psychological trauma, the UN Children's Fund (UNICEF) said.

The UN was also on alert following a series of more than 40 tremors and aftershocks in nearby southwestern Iran over the past two days, according to Byrs.

The governor-general of the city of Izeh has asked for 20,000 tents to shelter people sleeping in the open as a precaution.

The area includes three major cities -- Izeh, Masjid, Suleiman -- with populations of 100,000 to 150,000 inhabitants, and authorities fear the smaller tremors might be a sign of a forthcoming major earthquake.

TERRA.WIRE