The 34-year-old has not contacted relatives or friends in nearly a week.
She was last seen at her Upper Coomera home last Wednesday night and her four wheel drive was found in a street at Nerang on Monday night.
Police say it will take several more days to complete their forensic examination of Ms Chardon's home and car.
Detective Superintendent David Hutchinson says Ms Chardon's car remains the strongest lead.
"The focus of the investigation around the vehicle is in that area and we are doing doorknocks obviously in that area," he said.
"We are expanding that search out to locate anybody who can shed any light on the vehicle being left there."
He says there have been a number of reported sightings of a woman fitting Ms Chardon's description.
Superintendent Hutchinson says police need to establish who left the car in Bowden Street and when it was parked.
"We have had a very good response from the public and we have had lots of calls coming in from Crimestoppers," he said.
"We have a number that we are investigating at the moment - we have detectives now out there chasing them up, but we don't have a concrete sighting at this point.
"The longer this lasts the more concerned we become, so it won't be very long now it will be a full week and she hasn't made contact with family or friends and obviously we are very concerned for her welfare."
Superintendent Hutchinson says investigators are in regular phone contact with Ms Chardon's husband, who flew to Indonesia on business last Friday.
He says there is no set date for her husband to return to Australia.
"We want the same thing - if she is out there we want her to come home," he said.
"If she is not capable of doing that, we want to try to identify where she is and try to work out what her movements have been since last Wednesday night.
"Again we would make that appeal to the public - we would like anybody that has any information about Novy's whereabouts or her movements since last Wednesday night to come forward to the police."
Superintendent Hutchinson says Mr Chardon has told police his wife has gone off by herself for a couple of days in the past.
"I don't intend to go into detail of the conversation he is having with us, but he is available to us if we need him," he said.