NEW YORK CITY, New York (AFP) - Murders and shootings in New York have dropped to a new low, the mayor's office announced on Tuesday, as the city's controversial stop-and-frisk policy comes under fire in the mayoral race.

A statement from Mayor Michael Bloomberg's office announced that up until Aug 25 this year, 213 people had been murdered compared to 290 in the same period in 2012.

Murders committed with firearms plummeted 29.7 per cent, and there were 708 shootings compared to 957 last year.

The figures show that New York, once one of the world's most violent cities, is on track for a new record after 2012 saw the "lowest number of recorded murders and lowest number of recorded shootings in city history". In 2012 there were 419 murders and 1,374 shootings.

The latest crime figures were released as the police practice of randomly stopping individuals and searching them - seen as unfairly targeting young black and Hispanic men - is rapidly becoming a major campaign point in New York's mayoral election.

Several Democrat candidates have vowed to rein in the practice, after a federal judge ruled two weeks ago that it was unconstitutional.

Stop-and-frisk has been a centrepiece of New York's efforts to bring criminality to heel after the drug-fuelled violence of the 1980s and early 1990s.

Mr Bloomberg, completing his third and final term as mayor, has said the practice is one of the crime-fighting tools that has made New York "the safest big city in America".

"There is just no question that stop-and-frisk has saved countless lives," Mr Bloomberg said after the ruling.

"And we know that most of the lives saved, based on the statistics, have been black and Hispanic young men."