Five-hundred tonnes of personal protective equipment (PPE) destined for New Zealand's police officers, healthcare workers and defence force personnel is under the protection of armed guards.

The first of five chartered Air New Zealand Dreamliner flights carrying PPE has landed at Auckland Airport. The gear, purchased from China, is scheduled to arrive over the next 10 days.

Millions of disposable masks, gloves and wipes, as well as hundreds of thousands of coveralls and face shields, are being kept under constant armed guard until the shipments depart China.

National Express Products (NXP) CEO Joe Taylor, the country's largest supplier of commercial cleaning and hygiene products, says international competition for PPE has resulted in some "questionable tactics" to secure the gear.

"What we are seeing is a frantic scramble by world governments trying to protect their own people, significant supply constraints from the highest quality manufacturers and a subsequent bidding war," Taylor said in a statement issued on Thursday.

"A lot of companies around the world not used to dealing in China have not been able to export their PPE as they don't pass Chinese customs authenticity checks. New Zealand is not immune to this. NXP, which is Kiwi-owned, and our partners only deal with Government-approved whitelist factories.

"For those who are new to the competitiveness of the international supply chain, this situation may come as a significant shock - with many finding themselves operating in an environment which can only be described as the 'Wild West'."

The Chinese government has intervened, applying restrictions on the volume of products available for export. Taylor says this has added another layer of complexity to the sourcing of critical equipment.

"Despite our relatively small size as a nation, our company, the NZ Government and our supply chain partners on the ground have been developing strong relationships in China for some time," he explained.

"These efforts have now come to fruition and allow us to purchase sufficient quantities of PPE to meet the immediate needs of frontline police, the NZ Defence Force, healthcare and essential service workers."

The arrival of the millions of units of PPE will alleviate the pressure on local supplies and ensure essential services can perform their roles safely.

Taylor says bringing the supplies into New Zealand has required cooperation from a number of key partners including Government agencies, freight and logistics providers.