Courtney Ross knew what to do when she saw smoke and heard a smoke alarm go off next door.

She may be little, but three-year-old Courtney Ross knew exactly what to do when she smelled smoke next door.

It was her twin brothers' second birthday on June 15 and mum Rachel had just driven home with the kids after getting takeaways for dinner.

Courtney went to close the gate while her Mum got her brothers, Xavier and Sam, out of their car seats.

TERESA RAMSEY/FAIRFAX NZ The Ross family, from left: Xavier, 2, William, Sam, 2, Courtney, 3, and Rachel.

When she was closing the gate, Courtney smelled smoke and heard a smoke alarm in the attached home in front of their house in Ngatea, near Thames.

Rachel said she heard Courtney scream.

"All I heard was her screaming and I couldn't understand what she was screaming," Rachel said.

Rachel left the boys in the car and made her way over towards Courtney to see what all the fuss was about.

"She was saying, 'Mummy, Mummy the alarm's going, I can smell fire, we need the fire engines'. I thought that maybe it was in the paddock across the road, maybe there was a fire across there, so I went to have a look.

"And then as I went to shut the gate myself, I realised that it was the smoke alarm from [the neighbour's] house, I got a really strong whiff of the smoke myself."

Rachel ran inside to call 111 while Courtney got her younger brothers back into the car so they could escape down the narrow right-of-way to safety.

Courtney's firefighter aunt, Roseanne Hitchman, and grandfather, Ian Hitchman, were both on the fire truck when it arrived a few minutes later.

Firefighters quickly put out the fire, which was caused by a curry left on the stove unattended.

"By the sounds of it, it had been cooking for a number of hours," Rachel said.

"The firefighters said that given another couple of minutes, it probably would have been a full blaze and that we were lucky that we came home when we did."

A full-blown fire in their neighbour's home would also threaten their home because it was connected by a garage.

"That's why as soon as we found [the fire], I pretty much got these guys in the car and got the hell out of it because otherwise, we would have been stuck down here.

"My main priority was just getting out with the kids after Courtney alerted me to it."

Courtney's quick actions saved the neighbour's house, which was smoke damaged but okay, Rachel said.

However, the ordeal later affected Courtney, who wouldn't eat her dinner and was worried that her neighbour might become sick by the smoke-damaged house.

"That night, we had to ring Dad up to come round and talk to her because she was worried that the house was going to catch on fire again," Rachel said.

"She ended up falling asleep in Dad's arms, sobbing, and that's where she stayed for the night in the end, because she was pretty upset."

Rachel has been a firefighter for 16 years and also volunteers for St John.

Courtney's Dad William was a firefighter for seven years before joining St John in Thames full-time nine months ago.

Despite having both parents in emergency services, they hadn't really talked to Courtney about what to do in an emergency because she had gone through a stage of calling 111 to talk to her Dad, Rachel said.

They think she may have learned what to do in an emergency from her favourite TV programme, Fireman Sam.

Courtney's dad William said they were proud of Courtney's actions.

"For kids that age to recognise that kind of level of danger, it's amazing," he said.