A 75-year-old and a 16-year-old were among people tasered by police in New South Wales last year, according to government documents obtained under Freedom of Information.

NSW Police guidelines released in 2013 stated that an elderly person or a child should only be tasered in "exceptional circumstances".

"We see someone as young as 16 and someone as old as 75 that has been tasered in New South Wales, now that certainly does push the boundaries of what's acceptable within police guidelines," Opposition Police spokeswoman Jodi McKay said.

The reasons why the 75-year-old and 16-year-old were tasered have not been revealed.

"Certainly it would be important to know the circumstances of those cases," Ms McKay said.

"There is very little information that police will release about taser use however."

Ms McKay is concerned about the transparency of police taser use in NSW.

"We asked about complaints in regards to the use of tasers. They would not release that information," she said.

"We asked about the records of misplaced or lost tasers. They indicated they do not hold that information.

"The taser is a serious weapon and this information should be available."

The documents revealed that the oldest person to be tasered so far this year was 57-years-old while the youngest was 18.

Premier Mike Baird said police were "responding on the basis of threat" when a taser was used.

"It's nothing to do with age," he said.

"What we have to do here is, we have to back our police when they are responding to perceived threats.

"Any tasering event [that] does require a review well the police should be doing that, have done that and will continue to do it."

The ABC has contacted NSW Police for comment.