Covid 19 coronavirus: Trump tours mask factory - without a mask

President Donald Trump participates in a tour of a Honeywell International plant that manufactures personal protective equipment. Photo / AP

US President Donald Trump has issued a powerful statement to the thousands of Americans pushing back against mandatory face mask laws and other public health measures, touring a factory producing face masks without wearing a mask himself.

As the infection rate across the US continues to rise, Trump visited the Honeywell factory in Arizona, which is producing N95 masks.

Despite a sign at the factory's entrance reading "Please wear your mask at all times", Trump instead wore only the safety goggles provided, touring a factory floor populated solely by mask-wearing workers.

President Donald Trump participates in a tour of a Honeywell International plant that manufactures personal protective equipment. Photo / AP

Safety guidelines are posted as President Donald Trump tours a Honeywell International plant that manufactures personal protective equipment. Photo / AP

Trump has not yet been photographed wearing a mask and told reporters before he left for his trip to Arizona that he might wear a mask.

"If it's a mask facility I will, yeah. I don't know if it's a mask facility," Trump answered when asked.

The facility was producing masks and he did not wear one.

Trump is following on from Vice-President Mike Pence, who toured the Mayo Clinic last week without a mask.

Pence has since said he should have worn a mask while touring the medical facility.

The question of whether to wear a mask has been highly charged in the US, where a security guard was recently slain for trying to enforce mask laws at a food store in Michigan and other Americans have been seen trying to side-step the rules.

President Donald Trump (no mask) and all workers (masks). Photo / AP

In NZ, Dr Ashley Bloomfield said debate over the effectiveness of masks remained divided.

"You can find very high-level specialists on both sides of the argument."

People not used to wearing masks might find it uncomfortable and be tempted to unconsciously use their hands to adjust them regularly, potentially bringing germs from surfaces they touched into contact with their faces.

If masks became wet on people's faces, viruses, such as Covid-19, could also transmit through them, he said.

• Covid19.govt.nz: The Government's official Covid-19 advisory website