The foreign fishermen who've tested positive for Covid-19 in Christchurch were given a recognised test before boarding the plane

Eleven have returned positive results at the Sudima Hotel and 14 other cases are under investigation.

They're among 440 fishers from Russia and the Ukraine, 270 of whom are due to go out on three Independent Fisheries boats next month.

General manager Mark Allison says all crew had to have nasal swabs before leaving Russia, and were made to self-isolate.

He says they didn't get off the plane in Singapore, where it stopped for one and a half hours to refuel, and came straight to New Zealand.