Firefighters say the death of a 79-year-old Whanganui woman on Thursday could have been prevented with a working smoke alarm.

The woman was able to call 111, and was rescued by firefighters and revived at the scene before being rushed to hospital in a critical condition.

She died later that day from her injuries.

The blaze is believed to have been caused by an electric blanket in her room.

A smoke alarm was installed in her home, however it didn't have a working battery.

The Fire Service says if her smoke alarm had been functioning, it would have given her more warning and more time to escape