Liberal leader Peter Dutton has apologised for boycotting the National Apology to the Stolen Generations in 2008.
Mr Dutton, who was the only Opposition frontbencher to abstain from the apology, says he was wrong for not supporting it.
"I failed to grasp at the time the symbolic significance to the Stolen Generation of the apology," Mr Dutton said.
"It was right for Prime Minister [Kevin] Rudd to make the apology in 2008."
Mr Dutton has previously acknowledged he made a mistake boycotting the national apology, saying at the time he thought it should be made after the government had closed the gap between outcomes of Indigenous and non-Indigenous people.
Indigenous Australians Minister Linda Burney thanked Mr Dutton for saying sorry on the 15th anniversary of the apology speech.
"For some, the apology was something to reject and, of course, we all learn and we all grow," Ms Burney said.
She said Mr Dutton and his party now had a chance to work with the government by supporting the Voice to Parliament in a referendum.
"It is a good thing that we grow and we learn, but now we have the chance to do something practical together, to improve the lives of Aboriginal and Torres Strait Australians," she said.
"This is about getting things done and importantly for people to hold us to account.
"Governments are better when they listen and when they are held to account. Holding governments to account was not done in the era of the Stolen Generations."
On February 13, 2008 the government issued a formal apology to Indigenous Australians for the policies of successive governments of forced removals of Indigenous children from their families, who are referred to as the Stolen Generations.
The government estimates one in ten Indigenous children were forcibly taken from their families between 1910 and 1970.
Prime Minister Anthony Albanese said the graciousness of victims of those policies to come to parliament to hear the apology was an example to all Australians.
"I say to them, your courage showed us that when we are brave enough to acknowledge failure, we can find the strength to take the next step forward together," he said.
He said the country could take that next step by enacting a Voice to Parliament.
"The people of Australia through the invitation embodied in the Uluru Statement have been asked to travel on this journey. We have a chance to add a bright new season to the calendar and a future that embraces all of us," Mr Albanese said.
Shadow Attorney-General Julian Leeser, a supporter of the Voice, said the anniversary was a chance to remember to listen and include Indigenous voices.
He said the government was failing to close the gap, and repeated calls for a royal commission into the abuse of Indigenous children.
"It's in our national interest to heed the voices of Indigenous Australians that are speaking now. We must pay attention to the voices that do not already have a platform in Australian public life," he said.
"If we're to break the cycle we cannot afford to ignore these voices any longer."
