Prime Minister Tony Abbott has announced a further $20 million in aid to help the Philippines in the wake of Typhoon Haiyan - taking Australia's total contribution to $30 million.

Mr Abbott says the additional money will be used to address serious nutrition, child health and protection needs, as well as to purchase emergency food and provide logistic support and non-food items.

"As a good friend and neighbour, Australia stands beside the Philippines as it deals with this humanitarian disaster," Mr Abbott said.

As part of the new package, millions of dollars are being given to the United Nations' appeal, the Red Cross and other NGOs.

Two Royal Australian Air Force aircraft carrying medical personnel arrived in the Philippines overnight to assist in the relief operations.

The Defence Force is preparing to provide water purification systems and power generators to the devastated city of Tacloban over the coming days.

HMAS Tobruk is also being made available to assist in the recovery effort if requested by the Philippines' government.

Transport, logistical problems impede relief work

Major logistical problems continue to hamper the enormous disaster relief operation in the Philippines after last week's typhoon.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 39 seconds 3 m 39 s Tacloban mayor justifies slow response to Haiyan disaster ( Stephen McDonell ) Download 1.7 MB

A lack of transport and blocked roads are still stopping aid workers from reaching many thousands of homeless and hungry people.

There are some small water purification trucks now in the city of Tacloban, and the military has brought the city by and large under control.

It is almost a week since the devastating typhoon struck the city, potentially killing thousands of people, yet emergency accommodation is nowhere to be seen and even the basics like food and medicine are still out of the reach of many.

The mayor of Tacloban, Alfred Romualdez, told the ABC there is neither enough vehicles nor manpower to do the job.

One woman who returned to Tacloban to search for her family says the scenes there are haunting.

"The moment I stepped out of that plane our airport was totally destroyed. It was like a no-man's land," she said.

"Trees uprooted from the ground, dead people in the street, flattened houses. Just people aimlessly walking around searching for food and water. And the stench of decaying bodies, it probably would haunt me forever."

Streets are still jammed with refuse carried in by the huge tidal surge.

The resumption of electricity and running water are a long way off.

The official national death toll stands at more than 1,700, and the local government in Tacloban says hundreds will have to be buried in mass graves.

The relief effort comes as residents in storm-ravaged areas become increasingly more desperate.

Eight people were crushed to death on Wednesday when a crowd of survivors stormed a rice warehouse in a town near Tacloban, an official said.

Typhoon victims queue for free rice at a businessman's warehouse in Tacloban city, which was battered by Haiyan, in central Philippines on November 12, 2013. ( Reuters: Erik De Castro )

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 2 minutes 37 seconds 2 m 37 s The Salvation Army's Colonel Wayne Maxwell speaks with ABC News Radio ( Sandy Aloisi ) Download 1.8 MB

The United States has announced it is boosting its aid response by sending more cargo planes and four Osprey aircraft to help reach the disaster zones.

The Salvation Army says the Philippine government underestimated the severity of the typhoon which has devastated the country.

The Australian territorial commander for the charity in the Philippines, Colonel Wayne Maxwell, says authorities are struggling to clear roads to assist those who have run out of food.

"The magnitude of the damage is just something that while they were expecting a large typhoon, the effects of it were not anything like they envisaged," he said.

"Those who would normally respond as first responders they've been affected themselves."

Colonel Maxwell says it may take 12 months for power to be reconnected in some areas.

"It's a catastrophe that has occurred and they are just trying to come to terms with how to best deal with basic things, that is clearing away debris, gaining access through roads, maintaining law and order, which is a massive challenge."

ABC/wires