These include two nurses - one at Lautoka Hospital where more than 400 staff have been in quarantine since Wednesday.
The hospital has been isolated after a male patient contracted Covid-19 and died last evening.
He has become Fiji's first community case to die of the virus and health authorities have concluded that he had caught Covid-19 in the community, and not in the hospital.
Dr Fong said "we suspect this patient was the source point of transmission to the two doctors at Lautoka Hospital who were previously announced as COVID-positive, but we still do not know how he contracted the virus".
He said this means his staff have "an extreme sense of urgency to stop the spread of COVID-19 in our communities, and to prevent more vulnerable Fijians from succumbing to this deadly virus."
The second nurse confirmed with Covid-19 worked at the Raiwaqa Health Centre, which has now been shut down with all relevant personnel and patients quarantined.
That woman's husband was today's third victim.
The fourth is a Tongan soldier who had travelled back to the Pacific with a Fijian soldier who was confirmed with Covid-19 last month.