Sydney and New South Wales coastal residents are in for more wet weather with showers and possible storms predicted throughout the Sunday.

The Bureau of Meteorology said central and southern NSW coastal areas would experience offshore winds, which caused havoc after ex-cyclone Uesi passed through to the south of the country.

Intermittent showers were expected through central Sydney and southern parts of the state on Sunday.

Thunderstorms were also expected to develop across NSW, including in the Snowy Mountains, parts of the northern rivers, Hunter, metropolitan, south coast, southern tablelands, south-west slopes, north-west slopes and plains, and northern tablelands forecast districts.

A severe thunderstorm warning was cancelled for the southern tablelands district early on Saturday.

On Sunday morning, a hazardous surf warning remained for the Hunter coast, Sydney coast, Illawarra coast, Batemans coast and Eden coast after dangerous seas battered the coast over the past few days, littering several beaches with debris. A 47-year-old man died at Bondi Beach after a large wave swept him and a woman into the ocean on Saturday.

Minor flood warnings continued for Richmond, Wilsons River, Clarence, Bellingen, Orara, Gwydir, Paroo and Weir rivers as well as for the St Georges basin.

The heavy rain has prompted water experts to closely monitor Sydney’s main water supply as ash and debris was washed into the dam, forcing authorities to use alternative water sources for the city.

On Friday, WaterNSW said sediment, ash and debris were clearly visible on the surface of Lake Burragorang, which is a part of Warragamba Dam.

As a result, the water authority temporarily shut off its supply of raw water to the Prospect Water Filtration Plant, which services Sydney, on 9 February.

Water was instead drawn from Prospect reservoir and the upper canal while WaterNSW worked to mitigate the potential risks to dam water quality.

Raw water was still supplied to the township of Warragamba and Orchard Hills.

Warragamba Dam will return as the main source of untreated water supply to Sydney over the weekend, a WaterNSW spokesperson said.

“Ongoing monitoring has confirmed confidence in the quality of water available from Warragamba,” the spokesperson said on Sunday.

Containment barriers were installed at three locations on Lake Burragorang to limit the amount of ash and debris entering the dam supply while experts continued to monitor the water quality.

More than 320,000 hectares of land around the Warragamba catchment have been ravaged by bushfires this summer.

In Queensland, flood conditions were expected to ease on Sunday, as swollen rivers continued to fall.

However, the Bureau of Meteorology said communities around the southern interior should remain cautious of flooding over the coming days.

Residents surrounding the Bolzan Quarry dam remained on high alert, as water continued to seep out of the 433 megalitre dam.

Locals were evacuated overnight on Friday after a landowner spotted a 3.5 metre hole in the dam on his property at Talgai, about 170km south-west of Brisbane, on Friday afternoon.

Southern Downs Regional Council said engineers have deemed the dam wall at risk of failure, and advised evacuees to stay away from their homes.

On Friday night, the council issued text messages to about 5,000 people warning of the dam failing and 12 properties were evacuated.

Major flood warnings were in place for the lower Condamine River and upper Balonne River.

On the Gold Coast, police were still searching for Yang Chen, 26, who disappeared in the hinterland area while walking near Gorge Falls in the Tallebudgera Valley earlier in the week.