An exit plan is being developed for international mariners in managed isolation in Christchurch.
The first intake of 240 crew members was due to leave a managed isolation facility on Tuesday after dozens of them who tested positive completed their stand-down.
This is now on hold, however, after health officials have confirmed a worker has caught the virus where they are staying at the Sudima Christchurch Airport hotel.
A second worker has since been confirmed as testing positive for Covid-19.
A Ministry of Health spokesperson said the community and public health team is developing an exit plan for the fishermen.
"This will involve a risk assessment for their release, including any testing requirements."
The spokesperson said they want to acknowledge the work being done at the Christchurch managed isolation and quarantine facilities.
"So far this year, hardworking staff across these facilities have supported more than 5,000 people in their return to New Zealand.
"It's really important to emphasise the overall success of this work - it's the hard work of teams at these facilities which is ensuring we have the best support in place to help keep New Zealand and New Zealanders safe."
All contacts of the two confirmed cases have been followed up and tested and all results we have returned to date are negative, with a small number outstanding.
All staff who worked at the Sudima Christchurch Airport Hotel since October 23 have been tested, and all the results have returned negative.
"At this stage we have not identified any further cases connected to these staff members, but we are continuing ongoing monitoring of their contacts and of other staff at the Sudima."