Victoria is the only Australian state or territory to impose an arbitrary limit on how long animals at shelters can be offered for adoption - a 28-day deadline where animals are often euthanased.

Animal Aid, which is contracted for pound services with Yarra Ranges Council, has joined more than six other state-wide agencies in an online campaign to ban the 28-day adoption deadline.

The shelters want the government to abolish the "28-day rule" and enforce the same codes of practice used by pet shops, boarding or breeding facilities which have no restrictions or time limits imposed.

General manager Nell Thompson said the holding period did nothing to improve the outcomes for the animals and it forced shelters and rescue services to play an adversarial role with the community and their supporter base. "The welfare and rehabilitation of the individual concerned must always be a priority, no matter how long the animal concerned is held."

Animal Aid spokeswoman Debra Boland said although most dogs at the shelter were rehomed in about two weeks, cat adoption was a major issue. "For the most part, cat welfare is 20 years behind dog welfare - they have very little support.

"We have a rehabilitation program, and specially trained volunteers to help our animals cope with being at the shelter, to keep them as sane as possible, but the adoption process needs to be individualised, assessed on a case by case basis, not by time."

Ms Boland said 41 cats were brought to the centre by the council last month.

"Of those cats five were reclaimed, four have already found homes, six have been euthanased due to severe poor health or temperament, 18 are out on foster and eight are up for adoption."

The www.stoptheclock.com.au campaign has been lauded by Animal Aid, RSPCA Victoria, Lost Dogs' Home and the Australian Animal Protection Society. Campaign organiser Mike Bailey said shelters should not be forced to kill pets they are trying to rehome.