The father of missing Belgian backpacker Theo Hayez has thanked the Australians working to find his son almost a month after he vanished in Byron Bay.
The family of Theo Hayez have thanked volunteers for their support as search efforts for the missing backpacker continue, bolstered by the arrival of Belgian police at the weekend.
The Hayez family held a special event at the Byron Bay Golf Club on Sunday to thank volunteers helping in the ongoing search, with Theo's father Laurent saying the support had stopped the family from being "on the couch with tissues crying every day".
The 18-year-old backpacker was last seen on CCTV walking through the popular seaside NSW town after leaving the Cheeky Monkey's bar about 11pm on May 31.
The last "ping" from Theo's phone was recorded on June 1 in the area around the Cape Byron Lighthouse.
Belgian police are expected to accompany NSW Police as observers in searches around Byron Bay in coming weeks after arriving on the weekend.
Theo's cousin Lisa Hayez welcomed their arrival, saying the family hopes they can help find answers.
"It's going to help us, the most people on the case the better it is," she told reporters in Byron Bay on Sunday.
"I know they're going to do it. If the Australian police and Belgian police work together it's going to be faster and everything. That's the point."
Dog, foot and aerial searches have failed to locate his clothing or phone, which volunteers feel could be key to learning his fate.
The 18-year-old's parents separately arrived in Byron Bay earlier this month to join the search.
The family has spent the last few weeks with a small army of locals who have conducted dozens of searches in rugged bushland and blanketed social media with missing posters.
Byron Bay Detective Chief Inspector Matt Kehoe said last week was difficult for police and volunteers as bad weather temporarily suspended searches.
"We have been working closely with Belgium authorities since the early stages of Theo's disappearance and I look forward to working closely with them in coming weeks," he said in a Facebook update on Friday.
A month after Theo's last signs of life, Laurent Hayez again thanked volunteers for continuing to search for his son.
"The support they bring to us (gives) us the force to keep face," he said.
"Without all the support in Belgium and here in Australia I think we would be on the couch with tissues crying every day."
Mr Hayez, in his first media appearance almost two weeks ago, pleaded with encrypted messaging service WhatsApp to divulge Theo's communications.
WhatsApp provided what it could to investigators - limited metadata - but a spokesman told AAP they are unable to decrypt and pass on the content of Theo's final known messages.
On Sunday Mr Hayez declined to comment further on the official investigation, saying simply that the family "trusts the police".
"Thank you to all of you, thank you to the Australian people," he said.
"A beautiful country, a beautiful people."
Ms Hayez, who was already in Australia when her cousin disappeared, described the young man as a "really happy guy".
"(Theo) is just an amazing young boy, really happy, friendly, always interested about anything," she said on Sunday.
Ms Hayez said the young nature-lover had just graduated school and took a year off study to travel around Australia before deciding what to study at university.
Theo's family will remain in Byron Bay indefinitely, she said.
"We don't plan to go home or anything," she said.
"We'll just see how we go."
Police searches will resume as weather clears with specialist resources travelling to Byron Bay to help traverse the most rugged terrain, Detective Chief Insp Kehoe said.
"Sadly we are no closer to knowing what happened to Theo but we will continue to work for the answers that his family so desperately need," he said.