His grandparents lost their home in the 2003 Canberra bushfires.

Andrew Reardon, who works for DHL Australia, was at the end of his shift, on his way to pick up his son from day care in Gungahlin, when he noticed smoke on Black Mountain as he exited the Parkes Way tunnel.

The 27-year-old, who was was heading northwards, stopped his van and made his way across the busy road to put out the grass fire on the side of Black Mountain about 3.30pm on Wednesday.

"I pulled up and luckily I had a fire extinguisher in the van," he said.

"I would have liked to have got across there a bit quicker but the traffic was quite busy.

"The fire was actually quite intense. It had kicked off pretty quick and it was quite ferocious going up the hill.

"I put out the border real quick, as quick as I could, and then came back and stomped out all the centre.

"A lady and her partner, they literally just drove past and saw me stomping it out, and they came back to make sure I was all right.

"I said, 'The [fire] truck's on its way. I've already called them, so they should be here soon and I've got to go because I've got to pick up my son from day care!'.

"So I couldn't actually stick around to see the firies but it was pretty much handled when I left.

"I just acted with instinct and I knew where the fire was, if it was to get up that hill, it would have been pretty severe."

Andrew said the fire could have been started by someone who had thrown a cigarette butt from their car but he couldn't be sure.

An ACT Emergency Services Agency spokesman confirmed numerous triple-zero calls were made about the fire which had been deemed suspicious and was now under investigation by ACT Policing.

The grass fire had been among four in the area attended by firefighter units on Wednesday.

A number of suspicious fires are under review by ACT Policing including four grass fires near Haydon Drive and Ginninderra Drive in Kaleen and another on Kambah Pool Road in Tuggeranong, both on Tuesday, and four small grass fires in Campbell behind the Ainslie Village last Saturday.

Firefighters and contractors with heavy machinery on Friday were also continuing to attend a large rubbish pile fire at Pialligo, first reported on Thursday. The ESA spokesman said the cause of that fire had not yet been determined so it had not been referred to police.

Andrew's actions, meanwhile, came to public attention when a listener rang in to 666 ABC to praise the efforts of the then unnamed DHL driver.

The Canberra Times was able to track down the civic-minded young dad who remembers well the pain experienced by his grandparents, Margaret and Johnny Reardon, who lost their home at Pierces Creek in the 2003 bushfires.

The late Mr Reardon was a forester who was trained to put out fires in the Canberra fringes. Andrew spent many a happy day out at Pierces Creek before the 2003 fires devastated the settlement.

Andrew, a former Erindale College student, also credited training at work for his reaction.

"We do fire training at work and WH and S stuff so they sort of train you to be quite a proactive kind of person," he said.

And it's not the first time he has come to the rescue.

A few years ago he was on his way to see his then partner in Nicholls when he spotted a fire on the local golf course which appeared to have been started by the sun burning through broken glass.

"I didn't have a fire extinguisher then so I had to take my shirt off and smack it out," he said.

So should he start wearing a cape?

"I've got friends who are volunteer firefighters and they do it day-in and day-out, and those people deserve more credit than me," he said.

But good things come to good people. Andrew and his wife, Lauren, and their seven-month-old son, Leo, coincidentally moved into their own home, their first, in Dunlop, on Friday.