A thinktank is calling for the country's hospitals to release their full stocktake lists of all protective equipment supplies.
Suppliers say demand for personal protective equipment (PPE) has spiked and they are struggling to source enough protective gowns.
Provision of gear is worrying health workers.
Ports of Auckland told RNZ it could prioritise getting containers of protective gear off the wharves if it was alerted to them by the importers.
The ministry has a pandemic stockpile list but it only details the number of masks.
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A full list should include nine items including gowns and oxygen tanks, and which hospital has how many, the institute said in its letters.
"Since late January the McGuinness Institute has been trying to understand what supply chain risks might arise if the epidemic in China became a pandemic," it said.
"We are working with a diverse number of people on this issue who would like to know this information, such as philanthropists, manufacturers, procurement officers, doctors and nurses."
MidCentral District Health Board took just two days to decline an Official Information Act request from the institute on 25 March, saying on 27 March that it could not provide the information about the quantities and location of PPE because it "has diverted significant resources from across the organisation to support the government's response to Covid-19".
RNZ has been contacted by three makers or suppliers of protective gowns this morning since Morning Report covered the PPE problems, saying they have stock or might be able to make gowns.