A man who was taken into police custody yesterday after witnesses said he brought a knife into an Auckland gym, causing panicked members to flee, has now been charged with seven offences.

The 45-year-old Sandringham resident could face up to seven years' prison if convicted of threatening to kill two people at the CityFitness St Lukes gym in Mt Albert. He is also charged with two counts of assaulting the same person, using both a knife and a chair as weapons, which carries a maximum sentence of three years' prison.

In addition, the man has been charged with having a knife on a commercial premises, possessing an offensive weapon with intent to use it for an offence involving the fear of violence and intentionally damaging the computer monitors at CityFitness.

He is scheduled to appear in Auckland District Court today.

A police spokesperson said yesterday that officers had taken the man into custody that morning after a disorder incident at the St Lukes shopping centre in which they received reports of him being "verbally abusive towards the public".

Although the man was quickly taken into custody, he was found to have injuries and was taken to hospital for assessment, police said.

No members of the public were injured, but witnesses described the scene to the Herald as chaotic and shocking.

A man has been charged with entering an Auckland gym with a knife, frightening staff and members. Photo / Google

A man started screaming at staff a little after 8am and was asked to leave but returned about 30 minutes later with a knife and began pointing it at people, they said.

"The receptionist told us some crazy guy came into the gym and started screaming at the staff but that he had left now, so someone just probably had a bad case of Monday," gym member Matthew Le recalled of the first incident. "So we all got back to training."

But as he was leaving the gym a short time later, getting into his car, he said he heard "everybody in the gym running at full speed outside as if somebody was chasing them".

"I rolled down my window and asked them what had happened and they told me the same guy came back and this time with the knife chasing everybody around," he said.

Another gym member also recalled a man wearing a black hoodie showing up twice yesterday morning.

"I saw the knife in his hand when he was running towards the machines," he said of the second incident. "I started running and told people to get out the back gate."

The man was hit by a car as he fled the business, the witness said.