While international aid efforts are intensifying, with New Zealand saying it will send two navy ships, relief teams are yet to reach some isolated communities devastated in the weekend tempest.
"42 Fijians now confirmed dead -- disaster officials continue to deploy teams to help those affected across Fiji," government spokesman Dan Gavidi tweeted, raising the toll from 29 given yesterday.
The Red Cross said the body count was likely to rise further as word filtered back from far-flung corners of the island nation.
Severe tropical cyclone Winston lashed the Pacific nation overnight Saturday, packing wind gusts of 325 kilometres (202 miles) per hour and leaving a trail of destruction.
In addition to the mounting death toll, Care Australia said the number of people left homeless had ballooned to 34,000, up from 8,500 two days ago, and was also inexorably rising.
Care spokesman Dylan Quinnell said preventing disease outbreaks was a major challenge.
"The main priorities, for the whole country really, is to make sure that people have clean water and adequate sanitation," he said.
Prime Minister Voreqe Bainimarama yesterday acknowledged the problem and asked for patience from affected communities.
"We realise the desperate position that you are in, how traumatic this is for you and your families... But as prime minister, I want you to know that we will not rest until we have reached you."
Former prime minister Laisenia Qarase said he held grave fears for his home island Vanua Balavu, which has not yet been heard from.
"I'm 75 years old and the damage I've seen, the extent of the damage, this must be the worst thing in living memory for Fiji," he told Radio New Zealand.
New Zealand's foreign minister said two naval ships would depart for Fiji this weekend carrying building materials, water storage tanks and medical supplies.
