A SIX-WEEK-OLD puppy dumped next to a bridge has been just one of many unwanted pets the Mackay Animal Rescue Society has saved since Christmas.

MARS animal co-ordinator Lee Norris said the number of abandoned and dumped animals had skyrocketed during the holiday period.

"We were very fortunate to have Christmas Day quiet but then it started up," Ms Norris said.

"The phones just haven't stopped over the last couple of days."

Meanwhile, RSPCA Mackay investigator David Ferrar confirmed the organisation would be looking into an incident in which two family dogs were killed on Wednesday night near Walkerston.

One of the animals was shot in the head while another was beaten to death before their bodies were dumped on the side of the Peak Downs Hwy.

The dogs' owners, the Birch family, have been left devastated by the senseless act of animal cruelty.

"It's been logged on as a complaint and I will be in touch with the Walkerston police," Mr Ferrar said.

"I have spoken to the owners of the deceased dogs this morning, and discussed their options with reference to an investigation."

Aside from the incident, Mackay had recorded relatively few cases of animal cruelty during the holiday period.

Anyone found guilty of animal cruelty could face fines of up to $100,000 and two years imprisonment, Mr Ferrar said.