The annual national campaign raises awareness of the issues and impacts surrounding missing persons on family and friends following the disappearance of a loved one.

Four Shoalhaven missing persons cases you might be able to provide police with information are Gordon Andrews, Burton Hoolahan, Wanda Mitchell and teenager Kathleen Harris.

Mr Andrews was admitted to the Culburra Retirement Village on Monday, December 10, 2012 and went missing from the facility two days later, Wednesday, December 12 at about 3pm.

Mr Andrews was 79 at the time and would now be aged 89.

He suffers from short term memory loss and had been displaying the early signs of alzheimers. He has been known to wander off in the past and had been located in Goulburn and Bankstown areas.

He is described as being 173cm, grey to white hair, wearing a dark blue T-shirt, blue shorts and runners.

Kathleen Harris, aged 16, was last seen at her home in Huskisson by a friend about 9pm on May 31, 1999.

She had planned to meet with friends the following day but never arrived. Her personal belongings, including her purse and keys, were located in her home, and family and friends have not heard from her since she went missing.

Police are treating her disappearance as suspicious and have not ruled out that Kathleen may have been murdered. There is a $100,000 reward offered.

She is described as 160cm, a slim, brown hair and olive complexion.

Kathleen would now be aged 38.

Burton Hoolahan was last seen at Bomaderry train station on May 1, 980. He has not been seen or heard from since this time. The family of Mr Hoolahan continue to search for his whereabouts.

He is described as being 165cm tall, of medium build, of caucasian appearance.

Wanda Rose Mitchell was last seen by her daughter sometime in 1983 leaving the Star Hotel in Milton, NSW. She has not been seen or heard from since. Wanda is decsribed as 155cm, with a small build, fair complexion and brown eyes.

Wanda would now be aged 82.

If you have information that may assist police to locate Mr Andrews or Ms Harris please call Crime Stoppers on 1800 333000 or use the Crime Stoppers online reporting page: https://www1.police.nsw.gov.au/.

Information you provide will be treated in the strictest of confidence.

The issue of missing persons in Australia is complex and multifaceted - more than 38,000 missing persons reports are submitted to police every year in Australia.

About 99 per cent of missing persons are located, often with the help of the community.

A missing person is defined as, anyone who is reported missing to police, whose whereabouts are unknown, and there are fears for the safety or concern for the welfare of that person. A long-term missing person is someone who has been missing for more than three months.