A man has been charged with murder after the body of a child was found inside a barrel in NSW's Blue Mountains overnight. 

The grisly discovery was made after an investigation was launched into the disappearance of a 9-year-old girl last week. 

The girl was reported missing from a wedding estate in Mt Wilson at 8.20am on Friday January 14, sparking a major air and ground search. 

Yesterday, officers attached to Strike Force Buena conducted a search in the vicinity of the Colo River, about an hour's drive from where the girl went missing. 

The body of a child was located in a barrel. The body is yet to be formally identified and police have established a crime scene at the location. 

At about 8.30pm last night police attended a unit on Riley St, Surry Hills, and arrested a 32-year-old man. 

He was taken to Surry Hills Police Station and charged with murder. 

The man was refused bail to appear in Central Local Court today. 

Acting Police Commissioner Karen Webb and NSW Deputy Premier Paul Toole was to address the media at 11.15am today. 

The 9-year-old girl was staying at this Mt Wilson property when she disappeared on Thursday afternoon. Photo / 9 News 

Police, SES and RFS crews have spent the past five days scouring bushland around the multimillion-dollar Wildenstein wedding venue, where the girl was staying with her mother and her mother's fiance. 

The 9-year-old usually lives with her grandmother in Coolangatta, Queensland, but was spending two weeks with her mother during the school holidays. 

The murder charges come as questions were raised over missing hours between the time she was reportedly last seen and when police were notified. 

Police were told she was last seen sometime on the afternoon of Thursday, January 13, though she wasn't reported missing until the following morning. 

While the exact time her family realised she was missing is not yet known, it is possible she was missing for anywhere between 15 to 20 hours before police were notified. 

University of Newcastle criminologist, Dr Xanthe Mallett, said it is "quite unusual" for there to be such a long period of time between the child disappearing and it being reported to police. 

"I think what is unusual is that she wasn't reported missing for a number of hours. That is quite unusual in a child disappearance," she told Sky News. 

"However, we don't know why that was." 

Mallett said the first 24 hours after a child disappeared were often critical to the investigation. 

On Saturday afternoon, Blue Mountains Police Area Commander acting Superintendent John Nelson said investigators had been working with the family. 

"We made a number of inquiries at the scene and commenced a search here in the Mount Wilson area and have been working with the family in terms of their time frame and how we progressed the search from there. 

"They've given us a bunch of information." 

When asked if the case was being treated as suspicious, Nelson said investigators weren't ruling anything out at this stage. 

"We are not discounting any scenario at this time because we can't. 

"It's a traumatic experience for her family. 

"We are here to pull out every stop we can to locate her, and that's why we have all the resources and are continuing [to search]." 

Car, boat seized during investigation 

The Daily Telegraph reported on Tuesday that investigators have turned their attention to a red ute which had been seen at the property. 

Police tow away a red ute as part of the investigation. Photo / 9 News 

Officers seized the vehicle after a man drove it to Penrith police station over the weekend to speak with investigators. 

The publication reported police were sifting through hours of CCTV footage from cameras around the area to track the movements of the car. 

Neighbours had previously told police they saw a car leaving the Mount Wilson property without headlights on at about 4.30am on Friday. 

On Tuesday, a neighbour told the Daily Mail his wife was reading at about 4.30am on Friday last week when she heard the sound of a car moving along the driveway. 

"She got out of bed and went to the window and saw a shadow moving," the man claimed. 

"It is very quiet here at night and you can see the headlights – there weren't any on." 

Investigators also seized a boat over the weekend for "further examination". 

Earlier this week there were reports that RFS volunteers discovered multiple sets of footprints on a trail not far from the property where the 9-year-old was last seen. 

One print seemed to be "very small and barefooted", Nine News reported. 

NSW Police Chief Inspector Gary Sims told reporters "certain items have been found and identified". 

"But unfortunately [they] haven't led to anything that gives us a definite indication of her location." 

- by Ally Foster, news.com.au