In addition, a team of Australian and New Zealand medical specialists have arrived in the Pacific nation to help.
Red Cross Covid-19 coordinator Lauren Bird, who is based in Suva, said many people felt back in April there was light at the end of the tunnel.
But she said this recent outbreak had reset the clock.
The bulk of cases were in the Suva-Nausori corridor, where about a third of the population is based, Bird said.
"The community transmission is a big concern and this is also happening on the back of Fiji already suffering with the borders closed for the year, people had already lost income or livelihoods."
RNZ Pacific correspondent Lice Movono, who is in Suva, said the Fijian government was reluctant to go into a national lockdown.
"To explain it very simply, they can't afford the national lockdown," she said.
"They're saying that restricting people from being able to go back to work and re-open businesses means from a public perspective they can't take their health into their own hands, in terms of being able to put food on the table."
To respond to the unfolding situation, the New Zealand Government signed off an additional support package.
"The assistance includes up to $5 million for the Government to deliver Covid-19 operations, and $5 million to local civil society organisations working directly with households to mitigate poverty risks, including through the provision of food rations," said Foreign Affairs Minister Nanaia Mahuta.
New Zealand is sending two medical specialists to join Australia's medical assistance team (AUSMAT) in Fiji.
"They will spend some seven days into MIQ and then a 28-day assignment which helps do two things, effectively support the on the ground response, but also undertake a bit of assessment about what else is required," Mahuta said.
An anaesthetist was part of the six-member Ausmat team that arrived on Monday night.
Mahuta said a Defence Force infectious disease specialist will be deployed in the near future.
As Fiji grapples with the outbreak, the nation's Health Ministry is continuing its vaccine roll-out, with another 50,000 doses of the AstraZeneca vaccine arriving on Saturday as part of the Australian government's support of one million doses.
New Zealand has pledged half a million doses, which Mahuta said was expected to arrive from July.
However, Prime Minister Jacinda Ardern noted AstraZeneca was yet to be approved by Medsafe.
"Until they're approved in New Zealand, we are unable to pass on those doses, so instead we have been working with Australia, who are able to help them with doses sooner into Fiji," she said.
Fiji now has more than 1500 active cases in isolation since this outbreak in April. Five people have also died.
