A man whose son found his loaded pistol and accidentally shot and wounded his little sister has been fined after pleading guilty to weapons offences.

Key points: The man faced seven charges after his loaded Glock was fired by his son

The man faced seven charges after his loaded Glock was fired by his son The magistrate noted the father would have been devastated by the accident

The magistrate noted the father would have been devastated by the accident The man was fined $2,500 with no conviction recorded

The 48-year-old, who cannot be named because of child protection laws, was charged with seven offences relating to improper weapons storage and grievous bodily harm.

At the time of the incident in May, police said it was a "tragic reminder" that weapons needed to be stored safely.

Police said the father had been cleaning the 9mm Glock pistol, for which he held a licence, in the bedroom of his Cairns home.

But when he exited the room, he left the gun in reach of the children.

The boy, aged nine at the time, picked it up and accidentally fired it into the shoulder of his sister, then six.

A Glock pistol similar to the one involved in the Cairns accident. ( NSW Police Force )

She was taken to hospital in a stable condition and, according to police at the time, narrowly avoided more serious wounding.

Today, defence barrister Martin Longhurst told the Cairns Magistrates Court the incident had deeply affected the family, some of whom had flown in from China to be present for the hearing.

"Importantly, he doesn't appear to be some rogue with respect to his firearms — he's been involved with firearms from a very young age," Mr Longhurst said.

He tendered documents about the man's weapons licensing and training.

"It's affected the son greatly," he said.

"My instructions are the mother is in court and she needed to be consoled for weeks."

Acting Magistrate Ross Woodford took into account the defendant's guilty plea, his lack of criminal history and a number of character references before fining him $2,500, with no conviction recorded.

"It would've been very devastating to yourself and you've indeed shown remorse," Acting Magistrate Woodford said.

The defendant was urged to follow through on firearms safety training he had since undertaken and to ensure all his weapons were unloaded and secured in future.

"You know what little children are like," the magistrate said.

"They can get their hands on anything and they'll play with it."