The 42-year-old was out on a boat with friends on Christmas Day when he told them he was going to swim back to shore, a distance of approximately 300 metres.

A storm struck the area a short time later and the man's friends saw him disappear under the water.

He failed to surface.

Police and other emergency services have been searching the dam since the afternoon of December 25, but have so far been unable to locate the man.

On Friday, Chifley Police District acting inspector Mick White said that investigations are continuing but the search has been scaled back.

"The search has been scaled back in terms of the police divers from Marine Area Command. They are no longer on site," he said.

"Police rescue will be out there on a daily basis conducting surveillance with their drone and also searching the foreshores."

Sadly, the police don't expect to find the man alive.

"At this point in time, it's turned to more of a recovery mission in terms of locating him, unfortunately for all concerned," acting inspector White said.

What has made the search so challenging is the depth of the dam and the vegetation beneath the surface.

"There are a lot of incredibly deep areas in the dam there that makes it difficult to search with the sonar technology that was being used," acting inspector White said.

"Also, a lot of trees are submerged in the dam there, where if you are looking for something it can be easily snagged or caught on any sort of debris under the water, so that hampers any recovery attempt in these kinds of situations."

ALSO MAKING NEWS: Thousands of Murray cod released into Chifley Dam

With the conditions being "so unpredictable", he said the body could be found within in 24 hours or even several weeks from now.

Despite this, Chifley Dam is fully operational again.

While swimmers and some other users were able to return to the water from Monday, powered watercraft had been prohibited.

That temporary ban was lifted on Friday, with all decisions related to dam use made in consultation with Marine Area Command.

Bathurst Aqua Park has also reopened for patrons.

Acting inspector White said that, given the man has not been located, dam users should be cautious while in and around the water.

"Exercise caution in that respect. Just be aware that if you do decide to go out and use the dam there is that possibility that you unfortunately may be the one to discover that person," he said.

"Err on the side of caution if you do decide to take part in any water activities out there."

Our journalists work hard to provide local, up-to-date news to the community. This is how you can access our trusted content: