Search teams have spent the past 26 days scouring the bush for any signs of the missing three-year-old who disappeared from his late foster grandmother's home on Benaroon Drive seven years ago.

One of the main focus areas of the renewed search is a patch of bushland on the corner of Cobb and Co Rd, just one kilometre from where William was last seen in 2014.

This search site has now expanded to the opposite side of Batar Creek Rd, with NSW RFS volunteers assisting police in clearing dense bushland. Markers have also been placed to section off the areas to be searched.

A stretch of bushland between Batar Creek Rd and Benaroon Drive has also been cleared this week.

Breaks in the weather over the past few days have no doubt been a welcome site for the search team. However, the recent wet weather has left the ground muddy, making search conditions arduous.

The creek that runs through the search site has also been drained this week due to the wet weather.

A faded red piece of fabric was found in the muddy creek bed on Monday (December 6) and has been sent away to be forensically examined.

The search team has found a number of pieces of material during the search which have all been sent away for testing. It is not yet known whether any of the pieces of material are related to the case.

Geomorphologist Jon Olley told the Daily Telegraph that bones of a child would likely break down in the soil that is currently being searched.

"The one thing we have going in our favour is the fact that (investigators) believe he was in a polyester suit. That doesn't break down and it's very resistant to actually fading as well," he said.

"There possibly would be bones, but given the level of bioactivity here, and the amount of humic acids that are in the soils, that would actually help break them down over time."

At this stage the search is expected to last at least another two weeks.

"The difficulty is getting ourselves back to seven years ago to make sure that we don't miss anything," NSW Police State Crime Commander, Assistant Commissioner Stuart Smith, told 2GB last week.

"Anything found in these areas is then processed through Newcastle and then it's sent to the Forensic and Analytical Science Service in Sydney.

"They are working around the clock to process anything that comes from the scene."

For our full coverage of the search so far, read more:

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