The offenders broke into a house along Atherton Street by prying open a door.

Once inside, they located a free standing safe in the corner of a bedroom of the house.

The safe contained a number of rifles.

The safe would have weighed in excess of 150 kilograms and police were investigating the possibility that it was dragged or carried by the offenders out of the house.

The incident occurred sometime between 7am and 8.10pm.

No other property was stolen from the house.

Mount Isa Police Inspector Paul Biggin said police were investigating the involvement of more than one person in the theft.

He said the theft of a number of rifles was being taken “very seriously” by police.

“We have concerns about what these firearms could be used for - police are focused on investigating this matter quickly so we can get these firearms returned quickly,” he said. “Someone must have seen something suspicious going on in the area and we urge them to come forward and talk to police.”