The NSW government on Wednesday said the Service NSW app had been downloaded three million times by the state's residents, while some 100,000 businesses were registered to use the app's QR code.

Use of the Service NSW QR code system has been mandatory since January 1, when it replaced the option to use private QR code systems.

Health authorities at the time said this measure made contact tracing simpler, as it prevented the use of fake check-in names or phone numbers.

NSW Customer Service Minister Victor Dominello said on Thursday that more than 32 million check-ins had occurred on the app to date.

But he also admitted only 71 per cent of surveyed businesses in mandated industries - which includes businesses in the hospitality, hairdressing and beauty sectors - had implemented the Service NSW system.

"There's room for improvement there - I want to thank the businesses that are part of the 71 per cent," Mr Dominello told reporters.

"The ones who are not, you have to lift your game - you have to protect your staff, customers, you have a broader obligation to the NSW community.

"Pen and paper, there's enormous irregularities you don't get with digital.

"We have to be fast, we have to be agile and we have to be laser-like, very targeted, and digital is the only medium to do that."

Mr Dominello on Thursday said 320 fines had been issued for health order breaches since the start of the pandemic, with four venues temporarily closed.

There are more than 200 health inspectors on the beat around NSW.

"We are prepared to close businesses down when they are flagrantly breaching public health orders and putting everyone at risk," he said.

"We don't want to shut businesses down - in fact, we want to do the opposite, we want to encourage businesses to stay open.

"But they must stay open in a COVID-safe way."

Some businesses have previously complained that requirements to use the app rendered their privately-purchased contact-tracing systems, some with more advanced technology, redundant.

Some private contact-recording systems incorporated facial recognition technology, virus hotspot screening and temperature-checking apparatuses.

Mr Dominello's remarks also come after a man was this week charged for allegedly becoming aggressive at a McDonald's in Kellyville Ridge in northwest Sydney when staff asked him to sign in using a QR code.

He allegedly verbally abused staff before pushing a cash register and printer off the counter and leaving the restaurant.

Australian Associated Press