Armed guards have been used to protect a shipment of New Zealand-bound personal protective equipment leaving China, a supplier says, as he described the scramble for PPE as "the Wild West".

A total 500 tonnes of PPE sourced by health equipment supplier NXP will be brought to New Zealand on five chartered flights over 10 days. The first flight - an Air New Zealand Dreamliner - arrived at Auckland Airport yesterday and a second landed today.

Millions of disposable masks, gloves, wipes, hundreds of thousands of coveralls, and face shields are in the shipments, according to Kiwi-owned company NXP.

The stock has been kept under constant armed guard from the time of purchase until they leave China, NXP said in a statement.

It will be used for essential workers in the police, healthcare and defence force.

It follows the arrival of a shipment of PPE on Sunday, paid for by New Zealand's Mowbray family, the owners of China-based toy company Zuru.

Six planeloads of PPE - containing 50,000 sterilised gowns, 100,000 litres of hand sanitiser, 140,000 alcohol wipes and 30,000 face shields, gowns and masks - were set to arrive in New Zealand, Anna Mowbray told Newshub. The stock would be sold to the New Zealand Government at cost.

At the time Prime Minister Jacinda Ardern welcomed the additional product, saying it would supplement the 400,000 N95 masks produced locally each week at a factory in Whanganui.

NXP chief executive Joe Taylor said there was international competition for PPE which led to questionable tactics being used by some countries.

"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 many companies around the world that weren't used to dealing with China had not been able to export PPE because they had not passed Chinese customers authenticity checks.

"New Zealand is not immune to this. NXP, which is Kiwi owned, and our partners only deal with government-approved whitelist factories."

He said newcomers to the scene might get a "significant shock ... finding themselves operating in an environment which can only be described as the 'Wild West' ".

The Chinese government had also intervened to restrict exports, making sourcing critical equipment more complicated.

The company, supply chain partners and New Zealand's Government had developed strong relationships in China which were allowing New Zealand to buy enough PPE to meet the immediate needs of essential workers, Taylor said.