The annual event, which turns 94 this year, was due to be held on Sunday.
Many people dress up in costume for the event.
St Clair Surf Life Saving Club chairman Cam Burrow said the beach had been "taking a hammering" with the recent weather and a lot of sand had eroded.
There was no safe way to access the beach, including through the alternative path by the St Clair Scout Hall and tennis courts.
If anybody injured themselves the only easy way back up would be all the way down by St Kilda Beach, he said.
The problems did not stop there.
With the New Zealand Professional Firefighters Union strike there was also no access to a warm water fire engine, which was an important safety feature for anybody who got too cold.
About 100 people usually turned up and it would be better to postpone the event so it could be run safely, it said.
The event would hopefully be back soon when the issue of access was addressed, he said.
