More than 100 infringement notices were dished out by police on Saturday, including 30 related to the three large gatherings.

One gathering involved 15 middle-aged and elderly men playing cards together in a Marrickville home, with each being fined $1000.

Another involved five men playing video games together at a Merrylands West property on Saturday night, while the third involved 10 people gathering at a Sydney Olympic Park unit for an 18th birthday party.

All attendees of these gatherings were also fined $1000.

Deputy Commissioner Gary Worboys said that of the 106 fines handed out on Saturday, six also went to people in Orange in regional NSW.

He noted that many Greater Sydney residents had proven more than willing to dob in their neighbours for rule-breaking behaviour.

Crime Stoppers has received some 1200 calls to date.

"Really we just need to see people take a conscious decision about their actions," Mr Worboys told reporters on Sunday.

"If you have to leave home, make sure that you take a moment to make sure that you need, in the first instance, to leave your home and then, if you have to, to do that in the shortest possible time frame.

"Police have always said they will be firm but fair ... we are now in a position where we need to be much more firm than fair."

NSW recorded 77 new local COVID-19 cases in the 24 hours to 8pm on Saturday and recorded its first death of 2021, a 90-year-old woman.

Premier Gladys Berejiklian has all but confirmed lockdown in Greater Sydney and surrounds - scheduled to end on Friday - will be extended.

Australian Associated Press