The trade union movement has appealed for all Australians to open their hearts and wallets for cyclone-ravaged Burma.

Australian Council of Trade Unions president Sharan Burrow has called for donations to Union Aid Abroad - APHEDA.

There's a desperate need for funds to help deliver clean water, food, shelter and medical assistance to the Burmese people.

"This is a humanitarian disaster on an unimaginable scale and we are asking all Australians to donate through Union Aid Abroad - APHEDA," Ms Burrow said in a statement.

"The disaster relief work is already underway by union-affiliated grassroots organisations on the ground.

"Funds we receive will go directly to our ... affiliated aid agency Norwegian People's Aid who will work to make sure the funds aid the people most in need."

The UN has said it would resume aid flights into Burma after a suspension triggered by a tussle with the military regime over two plane loads of goods meant for cyclone survivors.

The junta has refused to allow foreign relief workers to direct the relief effort after the disaster which struck a week ago, drawing condemnation from the United Nations and world leaders who urged the ruling generals to open their doors.

The wrangle with the UN's World Food Program cast further doubt on the regime's claim to be doing all it can to save the 1.5 million people at risk of disease and starvation after last week's devastating storm.

"The World Food Program has decided to send in two relief flights as planned tomorrow, while discussions continue with the government of Burma on the distribution of the food that was flown in today, and not released to WFP," said Nancy Roman, WFP director of public policy and communications.

UN chief Ban Ki-moon on Friday warned that survivors' lives could be at risk if the military leaders refuse international aid.

"If early action is not taken and relief measures put in place, the medium-term effect of this tragedy could be truly catastrophic," Ban told a media conference in Atlanta.

Earlier, the White House welcomed news from Burma that it would accept US emergency aid and said one military cargo carrying supplies would reach the country on Monday.

According to the military government, the death toll is almost 23,000, with another 42,000 missing, but the United States says more than 100,000 could have perished.

The situation on the ground is one of horror almost beyond imagining - with starving survivors picking for food in waterways littered with the bodies of the dead - and aid groups agree time is running out.

The military, deeply suspicious of any outside influence that could dilute the tight control it has kept on the nation for 46 years, insists that it will welcome supplies from abroad, but must distribute them itself.

In a sign of the tensions, a UN source said Ban Ki-moon has not been able to contact directly the head of ruling junta, General Than Shwe, to discuss opening up to the relief effort.

The row with the UN came shortly after the junta, which has a long history of thumbing its nose at the international community, announced in the state-run press that it was "not ready" to allow foreign experts in.

"The international community can best help the victims by donating emergency provisions such as medical supplies, food, clothes, electricity generators, and materials for emergency shelters with financial assistance," it said.

"Burma will wholeheartedly welcome such course of actions. The donors and the international community can be assured that Burma is doing its best."

An Australian Red Cross worker said the Burmese government has been cooperative during the relief process in the disaster-struck country.

Michael Annear, from Melbourne, a regional disaster response coordinator who has been in Burma since Tuesday, spoke to international media via a teleconference call.

Seven Red Cross workers, four of whom are Australian, now have visas to work in Burma, with more expected in coming days.

Authorities have been cooperative with the Burma-based Red Cross workers, Annear said.

Countless masses are suffering in the country's waterlogged southern delta, where huge swaths of terrain remain under water since Cyclone Nargis struck last Saturday, and entire villages were washed or blown away.

"I am angry with the government," said Dowla Shwe, a single mother with five children who said her house was one of the many that simply vanished when the powerful storm tore through her village.

She said the military had brought no aid or food - and that she feared her children would now starve to death.

"If they can't help," she said, "why not allow foreigners to come and help us?"

Aid groups have repeatedly said that foreign experts who specialise in moving aid through disaster zones and assessing which regions need help first are essential to keep more lives from being lost in the tragedy.

"The situation is getting critical," said Noeleen Heyzer, the top UN official for Asia.

"There is only a small window of opportunity if we are to avert the spread of diseases that could multiply the already tragic number of casualties."

Critics of the regime have warned relief organisations that if they do not supervise the aid supplies handed over, they may be snatched by the generals and never reach the victims in Burma, one of the world's poorest nations.

Looking ahead, the UN appealed on Friday for $US187 million ($A198.26 million) to provide aid over six months to Burma.

Despite the catastrophe, however, the generals insist they will hold a constitutional referendum on Saturday, brushing off criticism they are ignoring the plight of victims while devoting resources to the vote.

Opposition leader Aung San Suu Kyi's party said they should delay the vote, and that it is only intended to tighten the rule of the military that blocked her election win in 1990 - and have detained her most of the time since.

For more information, and to donate, go online to www.apheda.org.au.