Action by Churches Together International members are working on a long-term strategy to reconstruct and rehabilitate areas of the Solomon Islands washed away by Monday's tsunami.

The giant tidal wave, triggered by an 8.0 magnitude earthquake in the early hours of Monday morning, measured between two and 10 metres high in places and killed at least 34 people.

Thousands have been left homeless and at least 13 villages have been destroyed in the most severely affected Choiseul and Western Provinces.

The New Zealand-based ACT member Christian World Service has launched an emergency appeal to respond to the needs of those left homeless and begin the task of reconstructing damaged areas.

Ruth Liloqula from CWS's partner, the Lauru Land Conference based in Choiseul, reported that two metre high waves travelled up to 200 metres inland, causing major property destruction and contaminating drinking water. Her family home, which had already been damaged by the rise in sea level, was swept away by the tsunami.

CWS said it was clear that the immediate response to food, water, medical care and emergency shelter needs would need to be backed up by a robust longer-term commitment to the enormous amount of repair and rehabilitation work required. CWS will use the money raised from its appeal to support communities over the coming months as they rebuild and re-establish their lives.

The Anglican Board of Mission in Australia has offered funds towards the emergency response, while the US-based Church World Service will work closely with ACT International to monitor the situation and explore the most suitable relief and recovery strategy.

Surviving islanders have taken to the hills for fear of another tsunami. According to a Reuters report, as many as 5,400 people are crammed into makeshift camps in the hills.

World Vision aid worker Tanya Rad is in the provincial capital, Gizo. She told the news agency: "There have been many false alerts and warnings and people who have been back in the town have run back to the hills. The tremors have been quite strong."

With supplies of fresh water scant and lack of sanitation a continuing problem, disease is starting to break out in some of the camps.

"There's been an outbreak of diarrhoea up in the camps but some camps have not been reached yet," Rad said, adding that medical teams were already making their way to the affected camps.

The greatest challenge remains to get the aid to the group of tiny islands. The only option is by boat but many of the motorised canoes were swept away by the tsunami, says Rad.