The 40-year-old woman and her three kids — two girls aged nine and four, and a two-year-old boy — were last seen north of Brisbane at the Narangba Railway Station on Friday, July 5 around 10.30am.
Queensland Police are appealing for public assistance to help locate the woman and her children who have not made contact with family since last week.
Police say the woman and children are in the north Brisbane area and are likely travelling on public transport.
They say they hold concerns for the four as their disappearance is out of character.
The woman is described as caucasian, 168cm tall, slim build and blonde hair.
Police are urging the woman or anyone with further information to contact them via Police link on 131 444, Crime Stoppers on 1800 333 000 or crimestoppersqld.com.au.