UPDATE 5.30pm: A smaller, dedicated team will continue to search for Jack throughout the night, utilising four-wheel drives.
A full search team will rejoin the efforts from 7am on Monday, including a helicopter.
UPDATE 3.30pm: POLICE say they are "very concerned" for the welfare of a 14-year-old boy missing in Woodsdale, south of Oatlands.
Jack Rumsey vanished between 2.45 and 3pm from his south Woodsdale home yesterday.
He was last seen on the road to Buckland, a town south-east of Woodsdale.
He was wearing a grey shirt and dark coloured jeans.
He may have left home on an orange mountain bike, but did not have a phone with him at the time.
Police have called Jack's disappearance "unusual" but are not treating the situation with suspicion.
Cold conditions, low cloud and rain have so far made the search difficult for the 40 men and women from state police, fire and SES.
Crews are continuing to search for Jack along the road and surrounding mountainous dirt tracks.
"It's unusual. While he does actively shoot photographic opportunities, and we believe he took a camera with him yesterday, it's unusual for him to be absent overnight and we're concerned for his welfare," Inspector Matthew McCreadie said.
A neighbour said the teenagers disappearance was "out of character".
The search is likely to continue after nightfall, or as long as weather permits, according to police.
EARLIER: A SEARCH is underway for a teenager, last seen yesterday afternoon at Woodsdale, south of Oatlands.
Fourteen-year-old Jack Rumsey left his home at 3pm, but he has not been seen, or heard from since.
Police have this morning declared an active search for the teenager, but do not believe he vanished under suspicious circumstances.
About 40 people from the Tasmania Police search and rescue, SES and local Tasmania Fire Service members are involved in the search.
Jack is described as approx 170 cm tall, small build with grey/blue eyes and brown hair.
It is unknown what he was wearing but is believed to have a pushbike and a green open faced helmet with him.
Anyone with knowledge of Jack's whereabouts is asked to contact Police on 131 444