A battle over a zoo's plans to exhibit two seals has been soured by allegations of dirty tricks.

Parties on both sides of the debate about Brighton's Sea Life Centre have accused each other of foul play.

The centre has claimed protesters are handing out "misleading" leaflets to discourage people going into the centre in Marine Parade, next to Palace Pier.

Staff have also accused a demonstrator of stealing posters designed to inform the public about its plans to expand and bring in two seals, penguins and sea otters.

But Brighton Animal Action, which is leading the protests, said one of its members had been wrongly framed in an attempt to discredit the group.

Meanwhile, activists have printed 5,000 postcards against the plans and will start handing them out near the centre today.

The postcards invite members of the public to send their names to Brighton and Hove City Council, which will consider a planning application from the Sea Life Centre next month.

Toby Forer, centre manager, said: "The news that the protesters will be handing out postcards comes as no surprise to us. The reaction of the vast majority of people to our plans indicates that there is little sympathy for their alarmist propaganda and going to print is a desperate attempt to drum-up support.

"We will of course continue to provide visitors and the wider public with the facts about our proposals, and have confidence that they will continue to be persuaded by the merits of these proposals, especially in the area of animal welfare."

Protester Lisa Gooch, 27, from Tilgate, Crawley, was visited by police at 7am on Tuesday morning as part of investigations into the missing posters. It is alleged the posters disappeared on Sunday when Miss Gooch was running a stall near the Sea Life Centre. Officers found nothing at her home.

She said: "We have been running such a big campaign. We have got big organisations involved - the RSPCA and Born Free.

"It seems almost as if our campaign has been going quite well, then they start trying to give us a bad name.

"We have been going down there both days at the weekend for three months. It is all very peaceful."

Sue Baumgardt, spokeswoman for Brighton Animal Action, said: "I thought it smacked of dirty tricks. Maybe their posters have been stolen. It certainly wasn't by any of us."

Mr Forer said the posters cost about £55 each.

He said: "If we have evidence somebody has been stealing them, obviously we would press charges. It is our property that has been taken."

He added that the regular protests had been causing problems. "We have had to inform the police because they are trying to distract people from coming in and giving them information that in my view is misleading."