The nurses' union wants an urgent review of how managed isolation facilities are run, amid fears for the wellbeing of health workers.
New Zealand Nurses Organisation (NZNO) say the two health workers infected with COVID-19 in Christchurch are a result of "unsafe practices" and "structural problems".
A person working at a managed isolation facility tested positive for COVID-19 on Wednesday - a close workplace contact of the health worker who tested positive on Monday.
NZNO president Kerri Nuku says managed isolation facilities are threatening the wellbeing of health workers, where they are under-staffed, have insufficient access to PPE and do not have the support in place.
"Our members are telling us they are anxious and fearful," Nuku said.
"The woeful working conditions at these facilities are leading to unsafe practices which put their health at risk.
"This puts those they care for at-risk and poses a threat to the border and therefore the welfare of the public.
"This is important because it is our border control that sets us apart from other countries and keeps us all safe."
Nuku wants an urgent review of how MIQ facilities are run to identify systemic failures, as she feared more health workers may become affected.
"We need assurances across the board that our members will be cared for and safe because at the moment they are telling us they are not."
NZNO Industrial Adviser DHB David Wait said inadequate pay and problems with rostering was a factor.
"Counties Manukau DHB has taken steps to fix its payroll issues and has provided assurances to NZNO members about their hours of work.
"They are also engaging with us to address concerns over unsafe staffing and we believe they are taking these concerns seriously.
"However, we need urgent action over promises. Until these issues are resolved, finding sufficient staff will be especially challenging and the threat to New Zealanders will remain very real."
COVID-19 response minister Chris Hipkins says border testing strategies do need improvements.
"Ultimately, it will be something for the new government to respond to," Hipkins told Magic Talk radio.
"What it does show though, is that the testing strategy, that we asked for it to be implemented has been implemented but it highlights some things that we can improve on and I'll be looking to make sure that those are actioned as well."
Prime Minister Jacinda Ardern said on Tuesday Christchurch will not be facing an alert level move after the community case was confirmed on Monday.
"Definitely not facing anything like that," she said.
