New Zealand spy agencies say they're monitoring screeds of information from around the world, as debate intensifies on whether some countries are being truthful about coronavirus case numbers.

In recent days a US intelligence memo and UK Prime Minister Boris Johnson questioned the veracity of China's claims.

Stuff asked what, if any, studies local intelligence agencies carried out in relation to analysing Covid-19 case numbers in China, and what the spies thought of China's Covid-19 transmission and death statistics.

Kevin Frayer/Getty Chinese commuters wear protective masks as they ride bikes after leaving work in Beijing.

The agencies did not directly answer those questions but said the GCSB and SIS had "access to a significant amount of intelligence, including from our international partners."

A spokesman for both agencies added: "We are providing information and assessments to Government regarding the international context of Covid-19 in accordance with the National Security and Intelligence Priorities.

Getty Images Employees eat their lunch while staying 2 meters away from each other at the Dongfeng Fengshen plant in Wuhan, China. There have been questions about whether China has been truthful about the number of cases in the coronavirus epicentre.

"However, we cannot release details of intelligence we hold or briefings that are provided to government decision makers. This approach is necessary to protect our capabilities, methods and areas of focus."

In recent days, the GCSB was mentioned after security concerns were raised about Cabinet's use of Zoom remote working technology.

Prime Minister Jacinda Ardern said if the GCSB advised the Government to stop using Zoom, then it would follow the bureau's advice.

Boris Johnson's allies were reportedly livid with alleged Chinese "misinformation, attempts to exploit the pandemic for economic gain" and the country's animal rights record.

But the Chinese regime has rejected claims it obscured the true nature of the pandemic.

Foreign Ministry spokeswoman Hua Chunying said China's response to the virus was "open and transparent," Time magazine reported.

This week, Bloomberg reported the US intelligence community believed China had concealed the extent of the outbreak in its country, under-reporting both total cases and deaths.

"Some US officials just want to shift the blame," Hua said afterwards.

As different countries try different approaches to tacking the pandemic, the US and China have traded criticism about each others' responses to the pandemic.