New amendments to the Public Health Order mean all individuals who attend private gatherings or parties of 20 or more, risk a $1000 fine.
Effective September 14, the changes aim to ensure the safety of the community ahead of the expected increase in social gatherings associated with Christmas and New Year festivities.
Previously, only the host or organiser of a gathering was liable to be fined if the premises breached the Public Health Order.
However, the changes mean every attendee will be held responsible if a breach is declared.
The NSW Government said the introduced changes also aim to ensure the state does not experience a surge in reported Covid-19 cases.
NSW Police Assistant Commissioner Tony Crandell, who also heads the police Coronavirus operation, said police are expecting large gatherings of people to occur as the weather warms up and more social activities are held.
He is urging resident to not let complacency creep in, despite the low numbers of community transmission of Covid-19 in NSW.
Mr Crandell said while the majority of NSW residents are doing the right thing by obeying social distancing laws and restricting their movements, police will continue to target those who don’t.