The WFP-managed Pacific Humanitarian Air Service transported more than 15,000 kilograms of medical cargo on behalf of WHO from Manila, Philippines, to Nadi, Fiji.
The flight arrived in Fiji late on Friday, carrying 75 oxygen concentrators and accessories, 1000 pulse oximeters, 100,000 gowns and 100,000 masks from WHO's Regional emergency stockpile.
The medical supplies have been distributed to main hospitals across the island.
"Thanks to this Humanitarian Air Service flight, these supplies have arrived at just the right moment to provide a critical boost to our arsenal as we face our biggest battle yet against this virus," Fiji's Permanent Secretary for Health, James Fong, said.
There have been at least 368 deaths in Fiji since April, and hospitals are feeling the pressure due to the spread of the Delta variant.
"At a time like this, we cannot afford a single delay in getting medical supplies into Fiji," WHO's acting South Pacific Representative, Dr Akeem Ali said.
The risk of transmission in Fiji remains very high, and it comes as welcome relief to have more stock on hand, Dr Ali said.