New right to silence laws are being deemed unworkable by the New South Wales Police Association, which says lawyers are thwarting attempts to caution suspects.

The laws, introduced last month, mean jurors are allowed to draw negative inferences if a defendant refuses to answer police questions and then goes on to provide a new alibi or evidence in court.

NSW Police Association president Scott Weber says lawyers must be physically present when police tell defendants of the new laws.

But he says the lawyers are finding ways around it.

"Police officers are finding the right to silence laws more complicated than have previously been discussed or has happened in the past," he said,

"The biggest problem is that when police officers are trying to question offenders for serious or indictable offences, we're finding that lawyers aren't turning up, or they're giving advice over the phone.

"And yet again the right of silence is being used."

Criminal lawyer Jane Sanders says it is not a loophole.

"Whenever the police don't like the law and the application of the law, whenever the police don't like the fact they have to obey the law, the word loophole seems to be bandied around," she said.

A spokeswoman for the state's Attorney-General Greg Smith SC says the law is only new, and the government will be working closely with police.

The watering down of the right to silence has previously been criticised by the Greens and civil liberties groups.