A global shortage of Covid-19 testing kits is hitting Australia as other nations limit exports and keep equipment for their own use, the country’s chief medical officer has said.

State health ministers have reported shortages of reagents and kits used to conduct coronavirus tests in laboratories, as unprecedented demand for testing combines with limits on exports from other nations struggling to contain Covid-19.

Speaking at the council of Australian governments meeting on Friday, Australia’s chief medical officer, professor Brendan Murphy, said supply problems with coronavirus testing kits was a “temporary issue” but one that was hampering the scale of testing in Australia and across the globe.

“It’s a temporary issue, but it relates to the fact that a number of countries, where these consumables are made have probably put export controls over them to keep them for their own use,” he said. “We will work through it. We’ve got world-leading medical technology and will fix that issue, but it has caused a temporary issue with the scale of the testing that we can do at the moment.”

He also noted that Australian health authorities were, in some cases, testing unnecessarily. A new testing regime was being developed to ensure only those most at risk were tested, he said.

“We are working through that, working through a new testing paradigm so that we can make sure doctors only refer people who have a decent prospect of a positive test, and we are working through ways to significantly improve that supply chain issue.”

In the United States, there have been widespread reports of shortages of the testing kits used to isolate the virus’s genetic material, or RNA, so that it can be tested.

The West Australian health minister, Roger Cook, said a global shortage of personal protective equipment for health workers and reagents for Covid-19 tests had health department procurement staff scrambling around the clock to secure them. “That’s something of acute concern to us,” he said. There is currently a 72-hour testing backlog in the state.

The state’s deputy chief health officer, Robyn Lawrence, said new measures were being adopted to ensure only the highest-risk patients would be tested. Those wanting testing would need to bring evidence of overseas travel within the past 14 days, such as boarding passes, she said.

In NSW, authorities say laboratories are able to perform more than 1,000 tests a day at Randwick, Westmead and Liverpool hospitals. Four more hospitals are being given capacity to conduct coronavirus testing. Private pathology labs have also been contracted by NSW Health to assist in collecting samples.

The Therapeutic Goods Administration, which regulates medical devices, said it had given an exemption on the use of unapproved medical devices, including lab tests for Covid-19. This was done “so that those devices can be made available urgently to deal with public health emergencies”.

The administration said increasing demand for tests would likely prompt a review of the exemption to allow a wider number of testing laboratories, including private laboratories, to gain access to the tests.

“On 31 January 2020, the [exemption] ... was made in order to facilitate necessary access to certain kinds of medical devices that are used for the diagnosis, confirmatory testing, prevention, monitoring, treatment or alleviation of novel coronavirus (Covid-19) infection,” the administration said on its website.

“These tests have been widely used by members of the Public Health Laboratory Network in testing for Covid-19 in each Australian state and territory, and as the demand for testing has increased, a review of the exemption may be considered to allow a wider number of testing laboratories, including certain private laboratories to have access to the tests.”