NSW police handed out 736 fines in one day and the police minister is warning people to avoid a "mass gathering of a group of idiots" in Sydney this weekend.

A man in a COVID-19 Sydney hotspot has copped a $5000 fine among hundreds of others that police have issued as they warn people off attending planned anti-lockdown protests this weekend.

One of the 736 fines recorded in the 24 hours to 8pm on Tuesday was given to a Padstow man in the epicentre of the COVID-19 outbreak in the local government area of Canterbury-Bankstown.

Police checked on him in the morning but he then left that afternoon.

"Police were aware that this might occur," Deputy Police Commissioner Gary Worboys said on Wednesday.

After officers returned to the home they phoned the absent man.

"He tried to tell police that he was taking the garbage bins out, which was clearly not the case," Mr Worboys said.

He was fined $5000 when he returned home.

"It's not just a tick-in-the-box check that police and the ADF will do," Mr Worboys said.

In western NSW, at Mendooran near Dubbo, a man was reported to police after his car struck a kangaroo.

The man had arrived from Queensland 10 days prior and hired a car to travel around country NSW on the backroads.

He told police "he was sick of COVID-19 and he needed to get out and about".

The man was fined $1000 and directed to return to a fixed address in Sydney.

Premier Gladys Berejiklian says non-compliance is a major issue extending the state's lockdown.

"In one day alone, more than 400 people police know of across the state ... left their house for the wrong reason," she said.

Some 18,000 police officers are backed up with the support of 800 Australian Defence Force members in the three-week crackdown on non-compliance of public health orders.

Police Minister David Elliot warned officers would be out in full force on Saturday in Sydney to fine and arrest any anti-lockdown protesters.

"We're temporarily living with restrictions that we all want to see lifted, but the mass gathering of a group of idiots could mean that day moves further into the future," he said.

On Tuesday, workers were caught running from a construction site on the south coast at Kiama.

Five men were identified from local government areas of concern and issued fines.

After NSW reported another milestone number of 633 COVID-19 cases, Ms Berejiklian said police and the ADF had more people on the ground than ever before.

"We don't apologise for having that strong presence," she said.

"The future of our freedom relies on it."