The Assembly has run out of time to prevent circuses with wild animals from obtaining entertainment licences, environment minister Mark H Durkan said.
Around 2,000 people have signed a petition calling for a ban in Northern Ireland as part of a campaign spearheaded by Green Party leader Steven Agnew.
Mr Durkan said he shared their concerns about the welfare of animals in travelling circuses.
“A change to the entertainment licensing system will require primary legislation and there is insufficient time left to do so before the end of this Assembly mandate.”
Elections are due next year.
Mr Agnew has said, even with the best of intentions, a travelling circus cannot meet the “five freedoms” of an animal which include the right to behave normally and to be free from distress.
One of Ireland’s largest circus owners, David Duffy, has said health checks by vets were rigorous and vowed to contest such an “extreme” change in court.
Mr Durkan said officials in the Department of Agriculture and Rural Development were working with southern counterparts in the Department of Agriculture, Food and the Marine on the development of an all-island code of practice on animals in circuses.
The environment minister has established a licensing review group to make recommendations on a future system. The public consultation has just finished.
The USPCA has said it is opposed to exhibitions or presentations of animals in circuses.
It said they were performing to a time-table of acts which do not come naturally to them, as well as being exposed to ridicule and indignity.