A New Zealand doctor in Haiti says the country's health system was only "marginally functional" before the devastating quake and will now need international help to cope.
Dr Greg Elder, of the international medical and humanitarian organisation Medecins Sans Frontieres (Doctors Without Borders), said Port-au-Prince was a congested city with a big population and poor infrastructure.
Before the quake, it had only 21 public health facilities, including four hospitals, for its 3.5 million people, he said.
"It [the health system] is not able to cope with an emergency of this magnitude, and it will depend on international support and international organisations to fill the gap".
Dr Elder said structural damage to Medecins Sans Frontieres' three hospitals was so bad patients had to be evacuated to open ground.
First-aid centres were set up in tents, but had been quickly overwhelmed by people seeking help.
"Our teams have treated more than 1000 wounded people, including open fractures and other injuries, at our makeshift facilities," he said.
A charter flight carrying two surgical teams and equipment to set up a 100-bed tent hospital with two operating rooms was to arrive late yesterday and another 70 international staff would arrive over the next few days.
The New Zealand Government has pledged $1 million in aid to Haiti, and aid agencies are on standby to assist.
Foreign Minister Murray McCully said the $1 million contribution would be distributed through international relief agencies such as the Red Cross and the United Nations.
"As fuller assessments of the damage and the type of assistance required emerge, New Zealand may look at further contributions," the minister said.
International Red Cross disaster response specialists are expected in Haiti today, and the New Zealand Red Cross is in discussions with its international partner agency, prepared to send workers or equipment if requested.
It has given $50,000 from its emergency fund to add to the Haitian Earthquake Appeal started yesterday.
More than 680 New Zealanders sponsor Haitian children through the Tear Fund charity.