RSPCA Tasmania president Dr Paul Swiatkowski said the dog's death was one of the worst cases he'd ever come across.

The six-month old female Staffy was found in a waterway with a brick tied around its neck on Monday.

An autopsy has revealed it was still alive when thrown in to the water near a reserve that included a dog park on Pitcher Parade.

"It would have been subject to, in my opinion, torture and pain before dying," Dr Swiatkowski said yesterday.

"It would have undoubtedly been frightened ... its crime may have just been being in the wrong place at the wrong time."

Dr Swiatkowski said Tasmania's animal cruelty laws were out of step with community expectations. He said the minimum fine for keeping turtles in Tasmania was higher than the maximum fine for animal cruelty.

"Certainly the RSPCA is advocating for the judiciary to take animal cruelty related crimes a little bit more seriously," he said.

Despite backing recommendations to increase penalties nearly a year ago the government is yet to act.

The review of the Animal Welfare Act recommended maximum jail terms for aggravated animal cruelty be increased to five years.

The current 18-month maximum sentence is lower than any other state.

It is also recommended creating a special offence of intentionally killing an animal.

Asked about the dog at Blackstone Heights, Primary Industries Minister Bryan Green reiterated the government's support for increased penalties.

"I'm horrified by that particular episode and I would want to make sure people do feel the full force of the law if they do do that to animals, it's horrible," Mr Green said.

Anyone with information about the dog killed at Blackstone Heights is asked to call the RSPCA on 63328282 between 10am and 4pm.