He said the project had no known completion date and would cost much more than originally estimated, as complex repairs to the sea walls required a rare combination of an extra low tide, low swells and minimal wind.

The drawn-out project began in May last year, but came to a halt when the original contractor, Specialised Marine Services, went into voluntary liquidation and left the works in disarray last November.

The new contractor, local firm Affective Services, which made emergency repairs to open the pool for summer, will set up its work site at Austinmer Beach on Wednesday.

However, Mr Hyde said this week's big seas would need to subside before work could start.

"We can only work on most of the site at the extra-low low tide, and it also has to be no swell and minimal wind," he said.

"We were hoping for seven days in the next week, but then we got the high swell so we couldn't work yesterday and today. And we've just got predictions for Sunday that an enormous swell will come through again."

Once the "extra-low low tide" ends next Wednesday, the next potential window for work will be three days in early July, as all of May and June's suitable tides fall in the middle of the night, he said.

"We've got to have daylight, it's too unsafe to have people working in the dark," Mr Hyde said.

"There's probably only another four windows for the rest of the year that the tide will allow us to get access, and that's only if the swell lets us do it.

"It's in the hands of the gods."

The pool will be closed each time the tides and swells align to allow contractors to work, but will otherwise remain open.

Mr Hyde said there was no way to estimate how long the repairs would take, as pouring concrete required several days of foundation works as well as a decent stretch of good weather to stop it being washed away.

Workers had also discovered more holes in the sea walls since the start of the repairs, he said, which meant the scope of the project had completed changed.

That meant the costs would far exceed the council's earlier estimate of at least $700,000.

"It's going to be well past that. We haven't totalled the cost, but it's going to be an expensive project," he said.

"But the community said they want this pool fixed, so we have to spend what it takes."

Greens councillor and Austinmer resident Jill Merrin said she was "frustrated" by how long repairs had taken but said she thought the cost of the project was justified.

"It's something that the residents of Wollongong have said they want, it's part of our culture and part of our city's history," she said.

Austinmer Pool was an iconic pool, she said.