Caritas Australia put the confirmed death toll at 25, but many more are now feared to have perished, news reports say.
Rescue workers last night warned of a humanitarian crisis amid reports that entire villages had been destroyed, according to the Age.
The tsunami was triggered by a massive under-sea earthquake, measuring 8.1 on the Richter scale, that struck 45 kilometres offshore from the island of Gizo, a popular dive destination, at 7.40am local time.
With memories of the devastating 2004 Boxing Day tsunami still fresh, large areas of the Pacific region - from Australia to Hawaii - went on high alert for several hours.
At the height of the drama, the Australian Bureau of Meteorology issued a tsunami alert for Australia's east coast. The warning prompted the closure of beaches as far south as Sydney, and panic in low-lying areas of Queensland, where homes, hospitals and schools were evacuated and residents fled for higher ground.
Later, as the tsunami threat for Australia eased, there was criticism of the emergency response, and calls for a better early warning system.
A grave-faced Solomon Islands Prime Minister Manasseh Sogavare warned his country to brace for a higher toll. "I think we are expecting more," he said in a televised national address.
Chief government spokesman Alfred Maesulia said waves of up to 10 metres had swept through some coastal villages, destroying houses and other properties.
"Some people were seen floating on the sea during the big waves but it was very difficult to go near them," Mr Maesulia said.
Police said the hardest hit Western Province had hundreds of low-lying islands. Early accounts from survivors, eerily similar to those that followed the Boxing Day tsunami, suggested wide-scale devastation.
The Premier of Choiseul Province, Jackson Kiloe, said at least one village had lost its hospital, with local health centres and schools also devastated.
Assistance on the way
Meanwhile, the Australian Government has made an initial offer of up to 1 million US dollars in emergency and reconstruction assistance to the Solomon Islands Government, Radio New Zealand International reports.
The Caritas Catholic network is also mobilising assistance, with $10,000 already pledged by New Zealand Caritas.
Caritas Australia, which is now assessing the required response, has already launched an appeal
According to Caritas partners, the hard hit town of Gizo is under approximately five metres of water while the Catholic cathedral and Diocesan buildings located on the waterfront have been badly damaged.
Caritas Australia has a long-standing partnership with the Catholic Church Dioceses and Caritas of Solomon Islands. Adam Elliott, Caritas Australia's support person based in Honiara says "communications in Gizo are down and contact is still difficult".
Jamie Isbister, Caritas Australia's head of programs says "the main concern now has to be ensuring adequate shelter, safe drinking water and food is made available to the people who have been affected".
Donations can be made via the Caritas website (www.caritas.org.au).
Tsunami disaster in the Solomons (The Age, 3/4/07)
Aid assistance starts pouring into Solomon Islands (Radio New Zealand International, 3/4/07)
Caritas Australia responds to Solomon Islands tsunami (Caritas Australia, Media Release, 2/4/07)
LINKS (not necessarily endorsed by Church Resources)
Solomon Islands Government - Prime Minister & Cabinet
Caritas funds election booklet to support Solomons democracy (CathNews, 15/2/06)
Tsunami still on Caritas agenda (CathNews, 20/9/05)
Pope praises human solidarity after tsunami tragedy (CathNews, 4/1/05)
Total Catholic aid to Tsunami recovery effort now at $500m (CathNews, 21/1/05)
3 Apr 2007