Fiji has reported 636 cases of Covid-19 in the last 24 hours - a record number of daily infections.

The Health Ministry also confirmed six more deaths due to the Delta variant of the virus, bringing the toll to 39.

Three of the victims were partly vaccinated while the rest were unvaccinated and died either at home or on the way to a health centre.

Health Secretary James Fong said a 74-year-old woman from Delainavesi in Lami near the capital Suva was presented to the FEMAT field hospital in respiratory distress and died on the same day. She was not vaccinated.

"The second Covid-19 death is a 74-year-old woman from Raiwaqa in Suva who was admitted at the country's main hospital - the Colonial War Memorial Hospital - for treatment of a serious non-covid related medical condition. She later tested positive in hospital," Dr Fong said.

"After an investigation, her doctors determined that her death was caused by Covid-19 and not the prior medical condition. She was not vaccinated."

Dr Fong said the third death is an 80-year-old man from Suva.

"One of our response teams was called to attend to him at home and he was then transferred to the CWM Hospital after being assessed to have severe symptoms including shortness of breath."

He said the man developed severe respiratory distress and died two days later. The man had also received the first dose of the vaccine in the first week of June, however, he had not received the second dose.

"The fourth death is a 43-year-old woman from Makoi. She was admitted at CWM Hospital for treatment of a serious non-covid related medical condition and later tested positive in hospital.

"After investigation, her doctors have determined that her death was caused by Covid-19 and not due to her prior medical condition.

"She had received the first dose of the vaccine at the end of April. However, she had not had the second dose and was not fully vaccinated."

Dr Fong said the fifth death is a 70-year-old man from Nausori who was presented to the FEMAT field hospital in severe respiratory distress and died on the same day.

"He received his first dose of the vaccine in the first week of June. However, he had not received the second dose and was not fully vaccinated.

"The sixth Covid-19 death is a 63-year-old man from Nailuva Road in Suva who presented to the FEMAT field hospital in severe respiratory distress and died on the same day. He was not vaccinated."

Dr Fong said there has been one more death of a covid-positive patient but the death has been classified as caused by a serious pre-existing medical condition and not the virus.

Fiji now has over 5,000 active cases in isolation, with 37 deaths from this latest outbreak that started in April.