The milestone will be celebrated at an anniversary function at Newcastle Museum on Thursday night featuring an augmented reality Aboriginal acknowledge ceremony.

Guraki committee chair Rob Russell said those who served on the committee throughout its life had helped build strong links with the community.

"City of Newcastle has been a leader in driving reconciliation and seen many benefits from the expertise of an active Aboriginal community voice," Mr Russell said.

"Guraki provides high level strategic advice to assist council to better understand the perspectives and aspirations of local Aboriginal people.

"Into the future, Guraki will continue to foster a more inclusive Newcastle community, and to promote to Council the concerns and interests that affect Aboriginal people in Newcastle."

Lord mayor Nuatali Nelmes said the group's efforts, including having dual names gazetted for eight Hunter landmarks, were part of a proud history.

"Our reconciliation journey over the past 20 years has been inspiring, challenging and rewarding," Cr Nelmes said.

"Former Lord Mayor Joy Cummings' advocacy followed by the establishment of the Guraki Aboriginal Advisory Committee by the former lord mayor Greg Heys has ensured that Guraki's legacy includes the Aboriginal flag on City Hall flying permanently alongside the Australian flag, a symbolic message acknowledging the Awabakal and Worimi peoples as Newcastle's traditional custodians."