The Queen's Birthday public holiday would be replaced with a day celebrating indigenous culture and history, if Labor wins the NSW election next year.
Opposition leader Luke Foley on Monday said it was "an anachronism" to mark the birth date of a foreign monarch in the 21st century.
"We are fortunate here that we are home to the oldest continuous civilisation in the world," Mr Foley told reporters in Redfern.
"That is something we should want to celebrate."
Mr Foley described the move as "a small step in the reconciliation process" and said he would consult with the community to decide whether the change would happen immediately or after the current Queen's reign.
Labor considered creating a new public holiday but Mr Foley said he didn't want to "load employers and businesses up" with the additional expense.
There are currently 11 holidays spread across the calendar, but with none devoted to indigenous culture the "mix" was not right, Mr Foley added.
Aunty Norma Ingram, the party's candidate for Newtown and the first indigenous Australian to graduate from Harvard University, said Australia had "a bit of growing up to do" when it came to recognising indigenous history.
"When you look in this country, Aboriginal people seem to be a little bit invisible," she said.
"There are so many Aboriginal people who live right across this country and have done for over 60,000 years."
Counter Terrorism Minister David Elliott dismissed Labor's call as a publicity stunt.
"I'm confident most Australians will treat Luke Foley's latest attention seeking exercise with the contempt that it deserves," he said in a statement.
Mr Elliot, the Australians for Constitutional Monarchy campaign director during the 1999 Australian republic referendum, cited the 19-year-old vote as evidence for why the Queens Birthday holiday should remain.
He suggested it would be more appropriate to replace Labor Day with a "national indigenous day".
The move would be in addition to a Labor commitment to fly the Aboriginal flag on the Sydney Harbour Bridge every day of the year.
The party also wants to establish a treaty process in NSW to provide a truthful basis for reconciliation.
Kamilaroi woman Cheree Toka began the flag campaign and her online petition has so far attracted more than 87,000 signatures.
The flag is currently raised 15 days a year - on Australia Day and during reconciliation and NAIDOC weeks.
Ms Toka hopes to present her petition to state parliament in the final sitting week in November.