Family of missing Toowoomba woman fears the worst

Jana Armstrong's family hold grave concerns for the young mother. (ABC Southern Qld: Grace Nakamura)

Jana Armstrong was last seen alive on Tuesday, July 7, at her home in the Toowoomba suburb of Newtown.

Police have released CCTV footage of the young mother and her baby at a cafe.

Police and SES will comb bushland on the edges of Toowoomba on the weekend as the search intensifies.

The family of a young woman missing in Toowoomba for three days say they have given up hope of finding Jana Armstrong alive.

"You won't see her walking around in public. You just won't. Hence why we're searching in bushland," sister Faith Isaacs said while cuddling her baby nephew.

Police have revealed that Ms Armstrong's car, a white Hyundai Kona, was seen in three different locations: Rangeville, on the eastern edge of Toowoomba, at Preston on the Great Dividing Range south of the city and at Darling Heights, south-west of the CBD, between the hours of 9pm and 10:15pm on July 7.

The car was then back near her home in Newtown between 3am and 5am on July 8.

On Friday, police and SES searched an area along Tabletop Drive at Rangeville and will continue searching over the weekend.

Detective Acting Inspector Brian Collins of the Darling Downs District said police were suspicious of the way in which Ms Armstrong disappeared.

Faith Isaacs is caring for her sister's four-month-old baby. (ABC Southern Qld: Grace Nakamura)

"The circumstances in which the vehicle was located down below from her address and she was nowhere to be seen immediately raised our suspicions," he said.

"The car was left sort of in an unusual spot, basically parked in the middle of the road.

"[it is] very alarming that a 30-year-old female with a four-month-old child disappears overnight."

Police are calling for anyone with information, CCTV footage or dash cam vision of the vehicle in the four locations to come forward.

Police have said Ms Armstrong's baby was found at her home but there had been no sign of her since last Tuesday.

Ms Armstrong's siblings, older brother Sam Davison and younger sister Ms Isaacs, say it is totally out of character for the young mother, still breastfeeding, to have abandoned her little boy.

Jana Armstrong was last seen at a Newtown address on Tuesday, July 7. (Supplied: Qld Police)

The family is calling on anyone with any information that could assist police to find their sister to come forward to police.

"If they have any information, to reach out, contact police immediately. And we would appreciate people helping by looking in their backyards or going for a walk