The Ministry of Health is investigating reports a person who flew into Tonga from Christchurch tested positive for Covid-19 while in Tonga's MIQ system.
The Ministry of Health said it was investigating reports in Tongan media of a positive Covid-19 result from a person who was one of 215 who boarded a repatriation flight to Tonga from Christchurch on Wednesday.
Tonga Prime Minister Pohiva Tu'i'onetoa made the announcement early this evening.
The infected person is still in isolation at the Tanoa Hotel in Nuku'alofa where passengers from the flight are in managed isolation for 21 days, but is expected to be moved to another facility.
Most of the passengers on the flight from Christchurch are seasonal workers and include most of the Tongan Olympic team.
All the people on the flight from Christchurch were required to have negative Covid tests prior to departure.
The Ministry said the case returned a negative pre-departure test before leaving New Zealand. They are fully vaccinated with the Pfizer BioNTech vaccine and had their second dose on 15 October.
"They were tested in routine Day 0 testing yesterday and returned a positive result today."
The Ministry and the Ministry of Foreign Affairs and Trade, is working with Tongan officials to confirm the case.
It said there would be further updates on this tomorrow.
Two more cases of Covid-19 were confirmed in Christchurch this afternoon, taking the total to four.
Several locations of interest have been identified and closed for deep cleaning, including Ken's Takeaways in Bishopdale.
One of the original cases went there on Wednesday night, while awaiting their test result.
Another case, a truck driver delivered bulk goods to Lion Brewery's Hornby warehouse.
Christchurch's bus exchange was also added to the list.
The Christchurch City council said it had organised for a deep clean of the exchange and would ensure a higher level of cleaning of it on a regular basis over the immediate future.
The city remains at alert level 2.