The mother of a missing Sydney flight attendant says her son had been receiving homophobic threats and suffering from severe pain when he disappeared.

Benjamin Roper was last seen walking out of his Randwick home on Saturday evening before he disappeared.

His mother Michelle Pippen is devastated and is looking for answers.

"Someone like that can't just disappear, he's got to be found," she said.

Ms Pippen says she is hopeful her son has not met with foul play and has just gone into hiding.

"The pain thing was really getting him down a lot and then the threats so that was another thing, so maybe the culmination," she said.

"People crack under pressure and it may have just been another straw."

At the time of his disappearance, Mr Roper was heavily medicated to treat chronic back pain.

He was also the target of abusive homophobic threats.

Ms Pippen has described her son as a happy, popular and a fit 32-year-old and says his disappearance is out of character.

Mr Roper's co-workers raised the alarm when he failed to arrive to crew a Virgin flight to Bali on Sunday.

Police are investigating whether the threats played a part in Mr Roper's disappearance.

Worried

Detective Inspector Rohan Cramsie says they are worried he may have met with foul play.

"This situation is unusual and we don't want to close our minds to a number of possibilities," he said.

Superintendent Gavin Dengate said yesterday that police suspected Mr Roper may have come to harm.

"We know that his phone is still at home, we know that his car is still at home and he hasn't taken anything," he said.

"That in itself is suspicious, you put that together, knowing that he was from very much a loving and caring environment - it causes us some concern."

Superintendent Dengate says detectives are following a number of leads and have spoken to Mr Roper's employers.

But he says there is little in Mr Roper's private life to suggest a reason for his disappearance.

Mr Roper is Caucasian, 180cm tall with a medium build and brown hair.

He has two distinctive tattoos including a flame design on his upper right arm and the numbers 2035 on his back - a tattoo associated with the Bra Boys.

His friends have been running a campaign on Facebook to try and find him.