The family have been searching for him desperately since Monday last week and have not had any leads.
"The area has a lot of golf courses, then from there it's bush and then it's coastline," his friend told the Herald.
He hopes more can be done in the search for his missing friend.
"I think there's an element of [police] just being used to this kind of thing," he says.
"It might be normal to them but I've known Andrew for more than 20 years and this is not normal to us," the friend adds.
"He just doesn't do this. And this is where the concern comes from."
The family knows Olphert arrived home around 5.30am on Monday, June 17, then left again around 7am. He had been in touch with his mum recently and it is out of character for him to be out of touch for so long.
He has not been seen or heard from since then and there are no leads to follow on his case.
Olphert was last seen wearing navy and white striped jumper and navy/dark coloured pants.
He is Caucasian, between 175cm and 180cm tall, is of medium build and has brown hair.
His friend Luke, who is flying to Sydney tomorrow to help search for him, say family and friends are heartbroken and desperate to find him.
His brother, Simon Olphert, is already in Sydney trying to find him.
His sister, Lucy Olphert, has put out a plea for help on Facebook.
"Well this is certainly one of the hardest things I've ever had to share," she wrote, alongside a photo of her brother.
"With little leads or information to go off right now we are hoping that the power of social media may be able to assist in finding my brother. To my friends in NSW and to those who may have been in recent contact with him, please be vigilant and share this around the surrounding areas."
Olphert is a Caucasian man, between 175cm and 180cm tall, of medium build and with brown hair.
He was last seen wearing a navy and white striped jumper and navy/dark coloured pants.
Anyone with information on his whereabouts should contact NSW Police on 1800 333 000 - that number can be reached from New Zealand by dialling 0061 1800 333 000.