Emergency crews are continuing to scour rural grazing land near Richmond, 400 kilometres east of Mount Isa in north-west Queensland, in search for missing woman Tèa Wright-Finger.
It's been 11 days since the 19-year-old was last seen in a blue Toyota Prado outside of Richmond on the afternoon of October 16.
She was reported missing to police two days later.
Police on Thursday said the car had been stolen "as a result of a fraud-related offence".
Gordon Graham, area controller for Mount Isa SES, said crews were now searching outlying areas of scrub and pastoral land north-west of Richmond to look for any signs of Ms Wright-Finger.
He said they were focusing on areas between where the car was last reported and the cattle station she worked on.
"We are concentrating on the thick-growth areas. We have covered all the open areas now. We are really getting into the thick country that we have to get in and start walking through it," Mr Graham said.
He said the terrain was variable, and especially rough around the creeks and rivers.
"It is very dry but surprisingly we are coming across lots of waterholes from the storms over the last couple of weeks," he said.
Heat and humidity make for dangerous conditions
Helicopters and planes have also been tasked with the search from the air.
Earlier this week, the Mount Isa LifeFlight Rescue helicopter searched 700 square kilometres of land around Cloncurry, Four Ways and Julia Creek.
Queensland police said Ms Wright-Finger's mobile phone gave a signal on the 18th, but has since stopped.
The signal was located to the Richmond area.
The vehicle has not been seen since October 16.
Mr Graham said the fact there was no car to narrow down the search area made it very difficult.
"We have just got to search the whole area where it was last seen and work out from that area where the vehicle was supposed to have been reported," he said.
He said if Ms Wright-Finger was in the scrub she would be struggling in the heat and humidity.
"[She] wouldn't be able to move, staying under shade because now the conditions are very dangerous. At this time, with the period they have been missing, there are concerns," Mr Graham said.
"We are getting storms coming in all the time now. It is getting wet, the humidity, all that is adding up to the time frame of survival."
'No car, no her'
Local Patrick Miller has been volunteering his time to help find Ms Wright-Finger, searching in his car and on foot.
"The hardest part is 'where is the car?' The car was her. Now no car, no her," Mr Miller said.
Mr Miller said he joined the search because he thought about his own family and his friends and what it would mean to him if they went missing.
"You see it on the news, and I would like to help and I am helping.The best I can, mate, but it's like finding a needle in a haystack. I have gone as far as the property Richmond Downs and all around this river. I have walked it," he said.
"It has been hot, rainy and humid. She left on Sunday and we had 28 millimetres of rain so it wouldn't be easy."
He said the scrub was very thick in places, particularly around the river areas where rubber vine is growing.
Mr Miller said he believed Ms Wright-Finger had parked the vehicle, got a lift to a party at another property overnight and then returned the next day on Sunday, October 16.
"Where did she go?" he asked.
He said while there was water in the area, Ms Wright-Finger would have to know where to look for it.
"If she knows what she is looking for she would be right. But it's hard, mate, if she doesn't know the land or the country she could perish."
Ms Wright-Finger has connections to Bundaberg. Police have urged anyone who may have seen her or her vehicle to come forward.
