HONIARA: A powerful aftershock rattled the Solomon Islands Sunday as aid agencies struggled to get a clear picture of the devastation four days after a 8.0-magnitude quake triggered a deadly tsunami.

The confirmed death toll rose to 10 with the discovery of a child's body in a ditch in the remote Santa Cruz Islands, while more than 3,000 people are squatting in shelters after their homes were destroyed.

Two boats carrying urgently needed supplies of medicine, food, water and tents have arrived at Lata, the main town in the island group, but the fragile communications system meant further shipments were on hold.

Officials in the capital Honiara said they had not been able to receive full assessments of the situation in the outlying islands.

"At the moment we don't know if we are still in the relief stage or have moved to the recovery stage," Red Cross secretary general for the Solomon Islands, Joanne Zoleveke, told AFP.

"We don't know if what we have sent is sufficient or if more is required and we have to charter more boats. We can't make those decisions until we receive assessment reports from Lata and communications are intermittent."

A 6.5-magnitude earthquake which rocked the region early Sunday was centred just 29 kilometres (18 miles) south-southwest of Lata at a depth of 18 kilometres, and followed a 7.0 aftershock late Friday night.

The Solomon Islands government has declared the Santa Cruz Islands a disaster area. Aerial surveys indicate most of the damage is confined to the Lata region.

It was estimated about 590 houses had been destroyed, with most of the destruction caused in the initial earthquake on Wednesday and the metre-high tsunami which swept through coastal villages soon after.

Initial reports put the death toll at 13, but Zoleveke said the intermittent communications with Lata indicated it was not that high.

"The official death toll is now 10 as of last night. The body of a child was found in a ditch," she said.

Australia pledged additional aid Sunday, with Foreign Minister Bob Carr travelling to the Solomon Islands to tour tsunami-wrecked areas. Canberra has already donated $250,000 to the local Red Cross.

Carr announced funding for an emergency flight of three doctors and three nurses to the devastation zone, with the return flight due to ferry severely injured patients back to the capital for treatment.

"We're deploying two AUSAID workers to get into Lata to assess the damage and help coordinate relief, and a medical flight to the disaster zone," he said.

"We'll fund the evacuation of two people injured in the tsunami to get hospital treatment elsewhere in the Solomons."

The Solomons are part of the "Ring of Fire", a zone of tectonic activity around the Pacific that is subject to frequent earthquakes and volcanic eruptions.

In 2007 a tsunami following an 8.0-magnitude earthquake killed at least 52 people in the Solomons and left thousands homeless.