Some 34,649 public health order infringement notices were issued between January 1 and August 31, 2021, according to figures produced by NSW Police to a parliamentary committee.

Of those, 34,627 are currently being prosecuted - a difference of 22.

Sam Lee, the police powers solicitor at Redfern Legal Centre, told AAP she has been "bombarded" with calls from people who'd been fined under the public health orders.

Her team believes there's a legitimate reason to appeal the fine in about 90 per cent of their cases.

In many cases, she said, the police officer issuing the fine appeared to get the law wrong. The COVID-19 public health orders have changed more than 70 times, she said.

One client was fined as they went to a chemist to get medication for a serious condition. Another was penalised for being in a shopping centre with their partner, who was unwell and could not be left at home alone.

Others were fined for entering an area of concern when they were only near the area, not in it, Ms Lee said. Some were engaging in lawful outdoor recreation, or drinking a cup of coffee outdoors instead of in a vehicle.

Ms Lee's clients include a 15-year-old who received a $3000 fine.

Despite her belief that the officers dispensing the fines often misunderstood the law, many of her appeals are being knocked back.

A person who's received an infringement notice can ask Revenue NSW to review the fine. But Ms Lee says the agency is sending reviews back to NSW Police, and that process lacks independence and oversight.

"Police are reviewing their own decisions really, and we're seeing this as a real fox in charge of the chicken pen situation," Ms Lee said.

There's another option - challenging the fine in court.

For many, however, it's too risky. They could end up with a criminal record, and a maximum penalty of $11,000 or six months in prison, if they're unsuccessful.

"There's no recourse, really," Ms Lee said. "They're stuck between a rock and a hard place."

Greens MP David Shoebridge said the fact police had dropped just 22 fines showed their attitude to review was: "Computer says no".

"$3000 fines are financially crippling for many people," he said.

"Many people will be saddled with their unfair fines because they are unwilling to challenge them in court.

"We have seen how unjust it is giving police the power to issue fines of this size during the pandemic and it's an experiment we should never repeat."

COVID-19 fines were increased to $5000 on August 16 as police launched a compliance blitz - Operation Stay At Home - amid escalating case numbers.

Revenue NSW data shows the number of fines rose sharply in July and jumped even higher in August.

According to a Sydney Morning Herald report, Police Commissioner Mick Fuller told his officers in August that they would not be held account for wrongly-issued fines as they had to take a "strong approach to enforcement".

A NSW Police spokesperson said those who believed they'd been unfairly fined could have the matter reviewed or go to court.

Officers had 24/7 advice available to them if in doubt before issuing a fine, the spokesperson said.

A spokesperson for Revenue NSW said all reviews are conducted on a case-by-case basis.

Australian Associated Press