He has not been seen since he left his family home in Bonner on September 26, 2017.

ACT Policing and ACT State Emergency Service will undertake a large-scale search of Mulligans Flat Reserve this weekend and next weekend in a bid to uncover new evidence.

The search area will encompass the nature reserve behind Bonner and Throsby towards the NSW border.

Police say after a re-examination of the case the decision to undertake the search was made in the hope of finding fresh evidence.

Jean's family has been informed the search is taking place this weekend.

Members of the public in the area are likely to see up to 50 people involved in the search between 7am and 5pm on Saturday and Sunday.

It also expected to continue on September 26 and 27.

The police investigation into Jean's disappearance remains active.

Anyone with information in relation to Jean's whereabouts is urged to contact Crime Stoppers on 1800 333 000, or via the Crime Stoppers ACT website.

Please quote reference 6158285. Information can be provided anonymously.