Rough surf conditions created by ex-Tropical Cyclone Iris prompted authorities to close 32 beaches across south-east Queensland on the first day of the Easter long weekend.
They included 11 beaches closed on the Sunshine Coast, 12 on the Gold Coast and a number of beaches at Yeppoon and North Stradbroke Island on Good Friday.
A number of beaches were later reopened as conditions eased into the afternoon.
A hazardous surf warning remains in place for the Capricornia Coast, Fraser Island Coast, Sunshine Coast Waters and Gold Coast Waters.
Lifeguards rescued 50 people from dangerous surf and strong currents, including 32 snorkelers at Moreton Island.
Gold Coast lifeguards banned swimming at beaches in Surfers Paradise, Mermaid Beach, Nobby Beach, Miami, North Burleigh, Tallebudgera, Palm Beach, Currumbin, Tugun, Bilinga, Kirra and Breaker Street at Main Beach.
On some Sunshine Coast beaches, conditions were so bad, lifeguards could not even get onto the sand.
Sunshine Coast senior lifeguard Trent Robinson said the high tides had washed away the beachfront in many places.
"[At] a lot of our beaches there's a big scarp, especially in northern beaches," he said.
"The tide's actually so high they're unable to drive on the beach. They can't get their equipment down there."
According to a Bureau of Meteorology outlook issued on Friday morning, ex-Tropical Cyclone Iris will "most likely move northwest over the Coral Sea during the next couple of days".
The system is expected to remain offshore of the east Queensland coast and below tropical cyclone strength, but is predicted to deliver heavy rain to central and northern Queensland from Monday.
Mr Robinson said Sunshine Coast lifeguards would reassess the conditions again on Friday afternoon.
He acknowledged the rough conditions had arrived at the worst possible time for holiday makers.
"It's really a perfect storm — we've got large tides, we also have large seas and a strong wind and we've got populated beaches."
He said lifeguards were urging beachgoers to stay out of the water, with conditions dangerous even in shallow water.
"With that really big tide that we've got it forms quite a large gutter so a lot of inshore movement," he said.
"So even [for] the swimmers who want to go for a waist-depth swim, it is really quite dangerous."
Lifeguards also warned the high tides would also create dangerous conditions in river mouths.
Cairns beaches are closed due to the removal of stinger nets.
