Potentially dangerous swells are set to hit the South Australian and Victorian coasts, the Bureau of Meteorology has warned.
Conditions in SA will begin to deteriorate from Friday morning with five- to eight-metre swells hitting exposed areas of the coast.
In western Victoria, swells will reach eight to nine metres before conditions ease over the weekend.
But the bureau says the forecast sea conditions will be the average across the affected areas and individual waves hitting the coast could be twice as high.
The warning comes after a 35-year-old father and his five-year-old daughter drowned after being swept from rocks by a large wave at Whaler's Way Sanctuary on the Eyre Peninsula on Easter Sunday.
On the same day, Victorian dairy farmers Ross Powell, 71, and his son Andy Powell, 32, died after their rescue boat flipped in a two-metre swell.
Surf Life Saving SA chief officer Damien Marangon has urged everyone going in or near the water to take responsibility for their own safety and the safety of those around them.
He also urged those tempted to head out into the surf on Friday and over the weekend to perhaps think again.
"Things can change quite quickly and dramatically," Mr Marangon said.
"As attractive as it may be to go out there, the thing that has to come first is your own safety and that of your loved ones."
Australian Associated Press