NSW Revenue says 33,121 fines will be scrapped following a landmark decision in the Supreme Court on Tuesday that found details of the offences were insufficient.

Millions of dollars will also be refunded to those who have already paid the fines.

A total of 62,138 COVID-related fines were issued in NSW during the pandemic, meaning roughly half will no longer be valid.

The announcement came about an hour after Justice Dina Yehia told a NSW Supreme Court hearing in Sydney that she would order refunds be given for two fines issued during last year's public health lockdowns.

Justice Yehia accepted evidence given on Tuesday that the fines were not valid because they did not include a sufficiently detailed description of the offences.

Katherine Richardson, SC, who appeared for the plaintiffs in the case against the NSW Police Commissioner and the Commissioner of Fines Administration, called for an immediate refund.

"It's accepted that the two penalties don't contain a description about the substance of the offence. We were in furious agreement over that," Ms Richardson told the court.

"It's only at the eleventh hour the Crown has finally accepted that these were invalid."

Revenue NSW said the decision to withdraw the fines did not mean the offences had not been committed.

"The Commissioner of Fines Administration is able to independently review or withdraw penalty notices," Revenue NSW said in a statement.

"In this case, he has decided to exercise his statutory power to withdraw two types of public health order fines."

The decision relates to fines issued to individuals and businesses for the infringement "fail to comply with noticed direction in relation section 7/8/9 - COVID-19".

The case was launched by the Redfern Legal Centre (RLC) on behalf of Brenden Beame, Teal Els and Rohan Pank, who were each fined between $1000 and $3000.

Mr Pank's fine was withdrawn before the case went to court, with the state agreeing to pay his legal fees.

Justice Yehia ordered the state refund $436 to Mr Beame and $826 to Mr Els, and said the men could also file applications to have their legal costs paid.

Revenue NSW has so far stopped short of also scrapping fines of the type received by Ms Els for "unlawfully participating in a public gathering", despite the court finding it was also invalid.

RLC acting principal solicitor Samantha Lee told AAP there was no legal standing to maintain the 162 fines issued during the pandemic for the public gathering offence, which total $489,000.

Figures obtained by the RLC showed COVID-19 fines were disproportionately issued to those living in low socio-economic areas.

"During the lockdown we were bombarded by calls from people who had been issued with COVID fines, so today we're ecstatic, it's a real win for the people," Ms Lee said.

CEO of the Aboriginal Legal Service Karly Warner commended the court's decision, and called on the government to cancel the more than 29,000 remaining COVID-19 fines.

"The government has dragged people through the courts only to concede that some fines may never have been valid in the first place," Ms Warner said.

"How many more people does it plan to put through this ordeal before accepting that all COVID fines must be cancelled?"

COVID-related fines unfairly targeted Aboriginal people and were continuing to cause suffering, she said.

The decision was also welcomed by President of the Law Society of NSW Joanne van der Plaat, who urged Revenue NSW to review the remaining COVID fines.

Many of the top fifteen per-capita locations for fines had high populations of Aboriginal people, including the most-fined areas of Walgett, Brewarrina and Wilcannia, she said.

Revenue NSW said the remaining 29,017 COVID-19 fines would still need to be paid if they were not already resolved.

Australian Associated Press