Family of missing uncle Kim Mackell seeks help to brighten their Christmas

As families get together to celebrate Christmas Day, one spends it as they have done every day of the week leading up to the holiday - distraught over a beloved uncle gone missing.

Kim Mackell, 64, has been missing since December 18 after being dropped at Central Station, following a Christmas barbecue in Ultimo with family and friends.

Missing man, Kim Mackell, last seen at Blackheath station.  Photo: Supplied

Fairfax Media understands Opal card information followed by CCTV footage was used to confirm with family that Mr Mackell got off the train at Blackheath, as intended, at 8.50pm that night.

It is believed he then waited for a taxi at the nearby New Ivanhoe Hotel, 250 metres south of the station on the Great Western Highway.

Missing man, Kim Mackell, last seen at Blackheath station.  Photo: NSW Police

He did not return to his home in Shipley Plateau, south of Blackheath.

His niece, Hillier Windsor has been in regular contact with police and a network of loved ones in order to do everything they can to help locate Mr Mackell, who requires regular medication for an ongoing condition.

There has been a widespread private effort to help jog the memories of anyone who might have come across Mr Mackell that evening, including posters put up throughout the Sydney Trains network.

"A large network of friends and family have canvassed everywhere. All the homeless shelters, all the hospitals - there's been no reportings yet but I've been getting a lot of phone calls," Ms Windsor said.

The family is keen to tap into public support with an understanding that police resources are stretched at this time of year and that any sighting might lead to the return of their uncle.

There is concern that after such a long period without medication, Mr Mackell may appear disoriented and vague, but is described by family as a "gentle, kind man".

Ms Windsor described the events leading up to her uncle's disappearance as inconsequential other than their festive nature - with no indication that anything untoward were to happen.

"We'd driven him down from the Blue Mountains that day, we all went down together - normal day, normal mood, normal things," she said.

"I know that he could have got on any train, but we kept [telling the police], 'He's such a creature of habit, he's a homing pigeon - he's done it for his whole life, he's not stupid.' "

NSW Police says it was notified of the disappearance on Thursday and is appealing for anyone with information to come forward.

"Mr Mackell is described as being of Caucasian appearance, of thin build, with grey hair. He was last seen wearing light coloured pants, a chequered shirt, maroon zip hooded jacket and boots," a statement said.

Police are urging anyone with information to call Crime Stoppers on 1800 333 000 or to use the Crime Stoppers online reporting page: http://ift.tt/1sPgN87