The start of spring means, for many, it's time for a 12-monthly check that a property's smoke alarms are in working order.

Turvey Park Fire and Rescue station officer Justin Bentley said it had been "a rough few weeks" for the Wagga community and firefighters.

He urged the community to get on top of testing in order to avoid further disasters.

"The number one thing that smoke alarms can save is lives," he said.

"That's what they're designed for, so if you get out of the house because of a working alarm, your life is saved and the rest can be replaced."

It is law for NSW residents to have working smoke alarms on every level of a home in which people sleep.

"That includes even mezzanine levels like drop down lounge rooms - if the roof level changes, you need a smoke alarm there," Mr Bentley said.

The station officer said there were two ways to test a smoke alarm.

"Every month you should be pressing the test button by either getting up a ladder or using a broom handle, and if it's a fixed wired system you should see a green light showing it's powered," he said.

"Battery back-ups or replaceable batteries also need to be checked and possibly replaced every 12 months, making sure everything is still in date."

While many believe they would wake from the smell of smoke if a fire were to ignite in their homes overnight, Mr Bentley said that was not the case.

"Smoke produced in the early stages of a fire is very toxic and actually induces you into a deeper sleep, it replaces oxygen with other chemicals so you won't wake up from that," he said.

"The pitch of some alarms is scientifically designed to wake you from even the deepest sleep, which is why it is so important to have them."

Wagga's RIC Electrics test smoke alarms in rental properties, with a representative saying a professional check every 12 months was essential.

"We use fake smoke to test the actual operation of the alarm, so it isn't just a matter of making sure they still make a noise when a button is pressed," they said.

The spokesperson also urged the community to avoid going for cheaper alternatives.

"It may seem fine to cut costs with these things, but you do get what you pay for and it's important to go to a proper electrical wholesaler to make sure you have the best working equipment," they said.