State Emergency Service volunteers from across the Sunshine Coast, Gympie and Noosa are continuing to search for a 14-year-old boy who has been missing for 12 days.

Key points: The missing teen's bike was found on Saturday

The missing teen's bike was found on Saturday Local bushwalkers have joined SES volunteers in the search

Local bushwalkers have joined SES volunteers in the search The area being searched is dense bushland containing numerous tracks

Police set up a forward command post as they look for Michael Ryan, who was last seen in the Landsborough area on August 7.

Teenager Michael Ryan was last seen on August 7. ( Supplied: Queensland Police Service )

Michael's bike was found in the Mooloolah Valley on Saturday, near where his mobile phone last recorded a signal.

The teenager was last seen on his yellow and black bicycle and was wearing a black jacket and wool beanie.

Acting Detective Senior Sergeant Grant Gleeson said police were still hopeful of finding the 14-year-old alive.

"With the help of media and the public hopefully we'll locate him safe and well — we're always positive and [that] would ideally be the end goal," he said.

He said despite more than 20 SES volunteers as well as police coordinating the search on Monday, there had been no other clues found about the teen's location.

Acting Detective Senior Sergeant Gleeson said police had been searching since the boy was reported missing, and refused to comment on concerns of some family and friends that more people should be added to the search.

"I don't know and I can't comment on family and friends and their concerns because they haven't addressed that with me," he said.

"I can assure you that the police are doing everything they possibly can in respect to the ground search that's being undertaken.

"The search hasn't just commenced on Saturday — police have been conducting many investigations from the moment that Michael was reported missing through to that time.

"Locating the bike enabled us to commence a point of origin of where to commence that search from."

Acting Detective Senior Sergeant Gleeson said the search would be suspended at dusk as the area was too treacherous to search at night.

"At this stage the searches will be done through daylight hours due to the terrain and the dense coverage there," he said.

"It is probably a little unsafe to be sending SES workers and police out to search in those types of environments."

'It's just a nightmare'

The boy's grandmother Lloma Dunne told the media on Friday the entire family was feeling the emotional strain.

"Very tough, very, very tough. It's a hard time," Ms Dunne said.

Ms Dunne said while Michael loved exploring the bush, it was very out of character for him to be missing for this long.

"He might be gone a few hours or something, gone into the bush and done things," she said.

"I'm appealing to any member of the public, if you've seen Michael, heard from Michael, would you please let the authorities know — even a snippet of information could be very, very helpful."

Family friend Tracey Disney said there were mixed emotions when the bike was found over the weekend.

Michael's bike was found in the Mooloolah Valley on Saturday, near where his mobile phone last recorded a signal. ( ABC News: Tara Cassidy )

"It gave us hope, apparently when they did searches not so long ago, a few days ago, they say that they didn't see that bike," she said.

"It just makes me think that we've got a bit more of an area. We know that his phone pinged up here, now we've got another clue that he could be in this area somewhere."

But she said she feared time was running out.

"We want to have hope, but it's just getting too long. It's getting too long now, it's 13 days ... it's just so hard, we're just trying to support each other through it all," Ms Disney said.

"We're devastated, we're just so scared, we're just so worried. We just have no clue, don't know what to think. It's just a nightmare."

Local bushwalker Kayne Meyers said he joined the search yesterday.

He said the area was tricky to search because there were so many tracks in the dense bushland.

SES volunteers prepare to search bush at Dularcha National Park. ( ABC News: Tara Cassidy )

"My brother and I just came after hearing that the young fella was lost somewhere in our local area," Mr Meyers said.

"We figured we'll just come for the walk and we'll explore some of the spots that we know in case we find any trace of the guy."

Mr Meyers said police and volunteers had been doing their best to find the teenager.

"It is concerning because he is a young bloke. I think the SES and police have done a pretty good, thorough job on the weekend.

"They're doing a thorough search where they can — I know the helicopters have been out as well."