Coastguards have warned surfers and water sports enthusiasts could be seriously injured or killed if they get too close to the wreck of the West Pier.
A canoeist had to be rescued on Monday when he capsized and clung to one of the pier's columns until he could be reached.
The lifeboat that went out to him from Brighton Marina was put out of action after hitting the jagged edges of the pier and has had to be replaced.
Dave Adamson, of Brighton Lifeboat, said: "Any lifeboat team will know the local hazards in their area and you take those into account when going out to deal with them.
"But people do need to take care, especially if they are unfamiliar with the sea and the environment. If someone goes out close to any structure in the sea they are potentially increasing the risk of injury."
Many surfers go out close to the wreck of the pier because it creates good waves.
Sand has built up on either side of the collapsed structure. This makes the seabed shallower and when incoming waves hit it they build up to a greater height.
Surfer Dave Clark was out at the West Pier when the canoeist got into trouble.
He believes the pier is not dangerous so long as people know what they are doing and pay attention to the tides and wind direction.
Mr Clark, 33, of Ventnor Villas, Hove, said: "As far as I know there haven't been any incidents like this in the ten years I've been surfing. I don't think the guy had a clue what he was doing."
The accident happened on the same day members of the Regency Square Area Society called for the remains of the pier to be cleared away.
Society chairman Roger Hinton told The Argus yesterday they want the rusting structure to be removed for safety reasons.
They also want West Pier Trust, which owns the pier, to be wound up so the skeleton can pass into public ownership. On hearing of the lifeboat rescue, Mr Hinton said: "That emphasises that the pier has become a danger to people using this part of the sea."
Geoff Lockwood, chairman of the West Pier Trust, said the accident did not change the trust's determination to see the pier restored to its former glory.
The trust is still in talks with English Heritage and hopes to reach an agreement on renovation within the next few months.
Mr Lockwood said: "What is left of the pier is not seriously dangerous. There are warning notices up and a navigation buoy off the end. If people are taking risks with their lives it is their responsibility."
A spokesman for the Seafront Office said: "The pier isn't, in itself, dangerous but getting near it clearly is, potentially.
"This year's main team of lifeguards start on Saturday. They will be keeping an eye out for people behaving irresponsibly and further signs will be put out in the sand at low tide to deter people walking to it."
Comments: Our rules
We want our comments to be a lively and valuable part of our community - a place where readers can debate and engage with the most important local issues. The ability to comment on our stories is a privilege, not a right, however, and that privilege may be withdrawn if it is abused or misused.
Please report any comments that break our rules.
Read the rules hereComments are closed on this article