Police are asking residents in the Townsville suburb of Wulguru to check their backyards as a major search continues for two boys missing in north Queensland.

The two boys, aged five and six, have been missing since late Saturday afternoon.

Police said the children were last seen at the intersection of Diamantina and Bullock streets at Wulguru about 4:00pm.

Searchers have found a green tricycle and a silver scooter the pair had been using before their disappearance.

Police said they hold concerns for their welfare.

Nicholas Baxter. ( Facebook )

The six-year-old is described as Caucasian in appearance, about 140 centimetres tall with brown hair, brown eyes and was last seen wearing a pale grey shirt and shorts.

The five-year-old is also Caucasian in appearance, about 120 centimetres tall with blonde hair and was last seen wearing white tracksuit pants.

Police, State Emergency Service volunteers, choppers, and family and friends of the boys are searching for the pair.

Police said the boys may have taken shelter last night and have asked local residents to check their backyards, garages and underneath their homes.

SES regional manager Daryl Camp said the search for the boys resumed at 7:30am.

"The SES teams have got 40 SES volunteers ready and they will be searching in the Wulguru area," he said.

Natalie from the local motel said it was not unusual to see young kids out on their bikes.

A rescue helicopter searched bushland for the boys. ( ABC News: Allyson Horn )

"There is kids everywhere," she said.

"I mean there's parks and kids always play in the streets and everything around that area as well.

"There's a little place called Flat Rock where they usually go swimming as well.

"It's a really good little community around that area but there is bushland as well so if they were unfortunate to go walking there is a big mountain ... it's not the safest place in the bush."

Police urge anyone that may have seen the boys to contact them via Crime Stoppers on 1800 333 000 or through their local police.

The boys may have separated so residents are asked to contact police if they see a boy alone.