When the state government more than tripled the on-the-spot fine for swearing in public last week, critics were left asking "what the f---"?

As part of the raft of legislation to tackle alcohol-fuelled violence, police will soon be able to issue fines of up to $500 to anyone that displays offensive language, up from $150.

But there is no official list of the words you will pay to use.

Scott Webber, from the NSW Police Association, said deciding whether someone's language was offensive was a “nightmare” and relied on subjective judgment.

He said fines were usually issued after an initial warning and particularly when f--- and c--- were used aggressively and in a public space, such as near a school, a main street or in a park.

But he said the police force welcomed the greater fine.

“We see time and time again offensive language being used in the CBD and across NSW ... the increase in fine [will] act as a deterrent but on top of that we need to make sure people are aware of the increase ... that it is a lot better than taking them to court."

Critics like solicitor Jane Sanders, from free legal service The Shop Front Legal Youth Centre, said swearing was part of everyday vernacular and the laws unfairly targeted minority groups like Aboriginal people and young people.

“The offence should be done away with altogether,” she said. “Increasing the penalties is not going to deter people from behaving in this way”.

“Police just don't like people disrespecting their authority, they don't like being sworn at – not because they're offended by their words, it's language widely used among police officers themselves, widely used by the community.”

The new fine is the highest on-the-spot penalty for swearing in Australia.

Police in Victoria can fine you $240, while in Queensland it will cost just $100 if you let one drop in public.

The only other state where fines are issued on-the-spot is South Australia.

NSW Premier Barry O'Farrell said the increased fine was “a sufficient amount to act as a deterrent for this unacceptable behaviour".

The criminal offence of offensive language is often part of a "trifecta" of infringement notices - the original offence, offensive behaviour and offensive language.

NSW courts have been reluctant to issue convictions over swearing – in 2010, Magistrate Pat O'Shane ruled that calling cops "f---ing pigs" was not offensive.

But the power that police have to fine offenders at the time of the offence means many incidences of swearing do not make it to court.

In the 12 months to September 2013, 4,289 incidences of offensive language were recorded, according to the NSW Bureau of Crime Statistics and Research. That number was down 10 per cent on the previous 12-month period.

In 2012, the NSW Law Reform Commission was inclined to suggest abolishing offensive language offences because the test for what was considered offensive was “subjective and difficult for an enforcement officer to determine”, the conduct caused “relatively minimal harm" and the fines were inconsistent because they depended on where the offence took place.

It recommended the government investigate further before abolishing the offence.

The Shop Front Legal Youth Centre was a stakeholder in the commission's consultation process.

A spokeswoman for Attorney-General Greg Smith, SC, said the government did not believe an inquiry into the offence was warranted.

“People have the right to use public places free from verbal abuse. The job of police is difficult enough without having to put up with offensive language by anyone, including people intoxicated by drugs and alcohol.”

Fines have also been increased for offensive behaviour (from $200 to $500), for intoxicated and disorderly behaviour following a direction to move-on (from $200 to $1100) and for continued intoxicated and disorderly behaviour (from $660 to $1,650).