Unbeknown to anyone, deep inside the 100,000 acre Expedition National Park bordering Mr Wagner's vast central Queensland cattle station, Brisbane's Steven Van Lonkhuyzen and his sons Ethan, 7, and Timothy, 5, had been stranded beside their bogged Mitsubishi Pajero for 10 days.

"I just sort of had a feeling they were in there," Mr Wagner said.

"I just did a job anyone else would do. I've got kids of my own and you put yourself in the same position and you just have to find them."

It was through what Mr Wagner termed his "outback church", a weekly Sunday morning prayer service with fellow station owners by phone, that he heard that Mr Van Lonkhuyzen and his sons were missing.

So the 54-year-old, who bought his 60,000 hectare cattle station at 18, went to find them.

"They were right down the other end, about 40 kilometres from my house, it's really rugged country so it takes you a while to get around," he said.

"It's pretty inaccessible."

People rarely access the park, Mr Wagner said, so when he found some tyre tracks early on in his search, he knew the trio were in there somewhere.

"The rangers have been away so there has been no-one out there at all," he said.

"I know the country pretty well so I worked out where I thought he was. I was fairly happy to find them. I was just happy to find them after the things that happened in Sydney and Cairns."

As were the trio happy to be found, he said.

"They were chucking their hands in the air, after sitting there for 10 or 11 days you'd be happy to see anyone," Mr Wagner said.

"I had some sandwiches and biscuits my wife had made with me, they were pretty hungry so they got stuck into them."

Mr Wagner said Mr Van Lonkhuyzen had rationed the food he took with them to feed the boys but had not eaten himself for the entire 10 days.

Ethan and Timothy had not eaten for seven days, Mr Wagner said.

"They had all lost a lot of weight, the boys were pretty bony, the little one's eyes were sunken," he said.

"But they were in good spirits, I was amazed how good they were ... the little five-year-old just wanted some eggs.

"He said to me, 'I just want some eggs, I've just been drinking water'. He would have asked me six times."

Mr Wagner said Mr Van Lonkhuyzen had out plastic containers to catch heavy rainfall in the area, which effectively saved all their lives in last week's hot and humid conditions.

"Lucky it did rain, so they had the water, if it had been dry, they would have perished," he said.

Mr Wagner said Mr Van Lonkhuyzen had placed a silver sheet on the ground near the car to attract attention.

He had also tried to light a fire but it been unable to in the damp conditions.

Though Mr Wagner found the trio at about 3.30pm Sunday, it took until well after dark for police and park rangers to arrive to get them out.

"I went away to ring the police and the boys didn't want me to go. I think they thought I wasn't going to come back," he said.

The boys were taken to hospital in Taroom, where they stayed overnight for treatment for starvation and dehydration.

Mr Van Lonkhuyzen, Ethan and Timothy left their home in bayside Lota on December 11, intending to chart an inland course to Cairns and arrive by December 15.

They became stranded on the day of their departure.

Mr Van Lonkhuyzen's wife raised the alarm when the trio failed to arrive by the scheduled date.

Attempts to contact her husband by phone also failed, with the remote location where they became stranded out of mobile phone signal range.

Mr Wagner said he felt confident an air search would have eventually located the trio, and downplayed his own role in locating them.

"I just happened to be the one that found them," he said.