A FIFO worker has gone missing after being dropped to Perth Airport on the weekend, with his mum making a desperate appeal to the public.

Bill Carter was set to return to his job at a mine site near Karratha on Saturday after a couple of weeks holiday overseas, but he never boarded his flight.

His mother Jenny O’Byrne said she dropped him to Terminal 3 after they ate breakfast together in Kelmscott, where she took a selfie of them just an hour before she last saw him.

He is described as being approximately 174cm tall, of slim build, with brown hair and blue eyes.

“That photo was taken just as we left The Dome cafe in Kelmscott, I said ‘come on lets take a selfie for your sister’ because she’d asked me whether I was with him, and that was about 12.20pm on Saturday,” Ms O’Byrne told PerthNow.

The 25-year-old was then dropped at the airport by Ms O’Byrne about 12.40pm, with his flight due to leave at 2.15pm.

Mr Carter only had a small 5L bag and was not carrying ample supplies, which wasn’t abnormal as most of his belongings were up at the mine site.

“I believe he may have had some phone contact with someone at 1.05pm, (but) since about 1.45pm on Saturday afternoon his phone has been switched off and nobody has seen or heard from Bill,” Ms O’Byrne said.

Fenner Dunlop’s operations — where Mr Carter was working in Cape Lambert on a 12 on, 9 off swing — confirmed on Monday that he didn’t board the flight on Saturday. The company has been supportive in trying to track Mr Carter down.

Ms O’Byrne, who has been a nurse in Bunbury for 14 of her 39 years in the profession, said it was vital to have as many people as possible looking for Mr Carter, as she is seriously concerned for his health.

“There are serious concerns for his outlook on life at the moment, so the police now are taking the missing persons concerns very seriously. He’s not well, and he’s very vulnerable and at risk and we just need a lot of people to keep their eyes out,” Ms O’Byrne said.

Ms O’Byrne emphasised that disappearing is really out of character for Mr Carter, but he has had a history of struggling with his mental health and had recently come off an anti-anxiety medication.

“This is completely out of character for him, he has been displaying some quite bizarre behaviours, he does normally take anxiety medication but he’s been off that for about the last 5 months and that was a scheduled tailoring off. But I think there’s been some other things that have gone on in his life, a situational crisis, and that’s so often the case in the mental health field,” she said.

Mr Carter was a student at Bunbury Cathedral Grammar School then studied at Murdoch university before pursing a FIFO career. Ms O’Byrne described him as reserved but widely loved.

“He’s a very quiet affable chap, he’s someone that everybody enjoys, he’s not loud and garish, he’s very quiet, he’s been going through some challenges recently and because he’s so quiet in nature, some of those challenges have been missed because he’s not very talkative,” she said.

“As a family we’re very supportive, I spoke to him a little bit on Saturday about what his concerns were, told him he has the full support of the family, we’re financially very solvent here and overseas, it’s just simply a case of when someone’s not well and they’re going through a situational crisis they don’t see the world as we would see it, they see it altered. “

Mr Carter had been on holiday with his Dad and sister in Zambia, where his Dad lives.

“His sister described him as ‘still quite sad’ when he was on holiday … we’re all very close although geographically we’re quite far. Bill isn’t a recreational drug user, he doesn’t smoke, and drinks minimal alcohol because of his work swing,” Ms O’Byrne said.

Ms O’Bryne urged everyone to reach out to family members, especially during the Christmas period which can be ‘lonely,’ to check in on each other.

“This is really a good lesson for everyone that mental wellness is prevalent, and is just so important in everyone’s family because you just don’t know what can cause them to be unwell,” she said.

WA Police have urged anyone with any information regarding the whereabouts of Mr Carter to contact police immediately on: 131 444.