IT'S been almost 30 years since Helen Karipidis disappeared from a Marrickville playground.
The 10-year-old had been playing with a group of her friends on December 22, 1988, before her father noticed she was missing.
She is one of the many people who go missing each year and police are again appealing for information about her whereabouts as part of Missing Persons Week (August 5-11).
They are also appealing for information about Qing Yue Chen who was last seen by his flatmate as he left their Dulwich Hill unit about 11am on Tuesday, October 24, 2000.
AFP Deputy Commissioner Neil Gaughan says many Australians live in constant uncertainty, not knowing if or when their loved one will come back.
DC Gaughan said that as part of the 30th NMPW activities, the AFP and its state and territory counterparts were also profiling 30 long-term missing people from around the nation on social media and outdoor advertising.
"It's important that we raise awareness of this issue, including the reasons why people go missing, the social and financial impacts, and how the community can get involved," he said.
"This might mean taking an interest and sharing our social media posts, or sharing a photo of an outdoor advertisement. After all, the community is our eyes and ears in these cases, helping police find the many thousands of people who go missing each year.
"If you recognise any of the missing people profiled this NMPW, or indeed any of the 2,600 long-term missing persons on the Public Register at missingpersons.gov.au, please contact Crime Stoppers on 1800 333 000.
"You might just have a piece of information that could help bring them home."