International aid was slow to trickle in to survivors, particularly in the hardest-hit town of Gizo in the western Solomons. At least 2,000 people spent a third unsheltered night on a hillside near Gizo following Monday's earthquake and ocean surge.

A New Zealand military transport plane unloaded an aid package of tarps, water and food rations in the town of Munda late Tuesday, following a shipment of similar supplies delivered earlier by a police patrol boat. Six doctors and 15 nurses reached Gizo on Wednesday.

A supply boat left the capital of Honiara on Wednesday night for the 10-hour journey to Gizo, but two others were delayed because provisions could not be found in the capital to fill them, chief government spokesman Alfred Maesulia said.

Frustrations were starting to show among survivors, many of whom fled the tsunami with whatever supplies they could carry.

"There's no water to wash, no water to drink," said Esther Zekele, who fled the tsunami waves with her husband and five children. The single sack of rice they brought to higher ground was half-empty, and no aid officials had come to their makeshift camp.

"We are just waiting, wondering why they haven't come," she said.

Getting aid to destroyed villages further afield could take at least two more days because of damaged roads, airstrips and wharves.

"We have not reached people as soon as we could ... because of the widespread nature of this particular disaster," said Fred Fakarii, chairman of the National Disaster Management Council.

Making things worse, many canoes and other boats were washed away or destroyed, and fuel was contaminated with sea water, Western Province Premier Alex Lokopio said.

At least 28 people were killed when waves up to 16 feet high smashed into the western Solomons following a magnitude-8.1 undersea quake. No significant tsunami waves were reported anywhere outside the impoverished islands, located northeast of Australia in the South Pacific.

Red Cross official Nancy Jolo said the risk of disease was rising in the largest refugee camp located near Gizo.

"What we are experiencing right now in some of the campsites is children starting to experience diarrhea," Jolo told Australian Broadcasting Corp. radio.

Fakarii said medical staff in Gizo had been overwhelmed by injuries and feared diseases such as diarrhea, cholera and malaria could break out because of the unhygienic conditions and lack of clean water and fresh food.

"The conditions at Gizo are such that these are likely things to happen unless action is taken quickly," Fakarii told The Associated Press.

Survivors terrified by the more than 50 jolts that have struck the region since Monday's quake — including several registering magnitude 6 or stronger — were afraid to come down from the hills where they had taken refuge, said deputy police commissioner Peter Marshall.

At one camp near Munda town, people perched on a hilltop peered out to sea with binoculars keeping watch for another deadly wave.

"I'm too scared to go home," said Winnie Tava, 32, whose house was nearly destroyed by the tremor. She and her husband grabbed their three small children and a few belongings and headed for higher ground, where they were joined by about 40 other families.

The family sleeps on a plastic sheet under a tarpaulin stretched between two wooden poles. They have a single aluminum pot for cooking rice, and a kerosene lantern.

"When there's no more kerosene, no more light," she said.

Authorities said they were somewhat relieved that aerial surveillance flights over the stricken coast had revealed "no evidence of mass deaths."