The family of a young woman who disappeared without a trace are convinced she has been murdered and are begging for a $1million bounty to unmask her killer.

Monique Clubb was just 24 when she vanished from a park in Beenleigh, south of Brisbane, in June 2013.

Her body has never been found and her family still have no answers about her fate, despite an intensive investigation over the last 13 years.

On the day she vanished, Ms Clubb had travelled from Hervey Bay to Brisbane with friends and called her mum, Sheena McBride, to say she would be home the next day. 

An inquest into her disappearance later found significant shortcomings in the police investigation, with the coroner saying critical lines of inquiry were overlooked.

More than a decade after she disappeared, Monique's family still cling to the hope of one day bringing her home.

They believe a $1million reward could be key to unlocking the mystery and persuading those with knowledge of her disappearance to finally come forward.

'We have been fighting and advocating for 13 years to raise awareness about Monique's disappearance,' her cousin Samala Cronin said in a social media video.

'We have literally had police officers and investigators shut us down at the very beginning when she went missing. We got told that she went on walkabout.

'Somebody in the community knows what happened to Monique. By having this $1million reward, it creates an incentive for them to come forward so that we can have closure.

'It's not fair what our family has gone through. It's not fair what my cousins have gone through and my auntie.'

Monique had long been a mother figure to her younger siblings and was deeply loved by her family.

She left her hometown of Hervey Bay on a Thursday, travelled to Brisbane for the weekend, and stayed in contact with relatives for the first two days. 

On the Saturday, she told her mother she would be home the following day.

Then all contact stopped.

Her family reported her missing and a police investigation was launched.

During enquiries, police discovered Monique had been 'doctor shopping' and had obtained a prescription for fentanyl using a false name.

Her family said she had turned to the drug after surviving a serious car crash years earlier and used medication to manage chronic pain which had led to addiction. 

The last confirmed sighting of Monique was by a security guard who saw her cross a creek after leaving a shopping complex.

The guard said the water was only knee-deep and that she crossed without difficulty before heading into a nearby park.

Police ultimately concluded Monique was intoxicated and died in the park after fleeing from the security guard.

Her body and belongings were never found. 

During the coronial inquest, Deputy State Coroner Jane Bentley was highly critical of the investigation, finding police had failed to properly examine key CCTV footage which showed Monique was not running and did not appear intoxicated.

'A lack of critical review and tactical decision-making led to gaps in the investigation,' Ms Bentley said.

'Those failures included an insufficient review of CCTV footage from Beenleigh station to determine whether Monique had boarded a train later that day, inadequate examination of phone records, and failures to investigate other public transport routes or review CCTV footage from South Bank station and other locations around Beenleigh.'

Monique's family are now asking the public to sign a petition demanding the Queensland Minister for Police and Queensland Police approve a $1million reward.

'Despite extensive investigations, coronial proceedings and years of advocacy, Monique's remains have never been recovered,' the petition states.

'Evidence presented during the coronial process, together with information gathered through ongoing investigations, strongly suggests that individuals within the community possess knowledge about what happened to Monique and where her remains may be located.

'A reward of $1million would provide a powerful incentive for those with knowledge of Monique's disappearance to come forward.'

The petition also stated the importance of allowing members of the public to provide information anonymously, ensuring 'those who wish to assist can do so without fear'.

'This petition is not only about accountability. It is about compassion, dignity and justice,' it adds.

'Monique's family have endured years of uncertainty and grief. They deserve answers. 

'They deserve the opportunity to bring Monique home and provide her with the respectful farewell that every person deserves.

'After years without answers, the time has come to do everything possible to bring Monique home.'