Australian PM Tony Abbott has vowed to "sweat blood" to secure constitutional recognition for indigenous people, saying he wants a referendum in 2017.
But Mr Abbott said he would not rush with the date until he was confident the referendum would succeed.
To be passed, the change must be backed by a majority of people in a majority of Australia's six states.
The constitution currently does not recognise Aboriginal and Torres Strait Islanders as the nation's first people.
Unlike in other nations settled by Europeans, such as Canada and New Zealand, Australia's constitution does not mention indigenous people.
In the past few years, there have been discussions about recognising them in a preamble to the constitution, and about changing the main part of the constitution to include a section that outlaws racial discrimination.
Aboriginal Australians represent about 2.5% of Australia's 24 million people. Generations of discrimination and disadvantage have left them with poor health and low levels of education and employment.
Speaking in Sydney on Thursday, Mr Abbott said he hoped the vote would be held in May 2017 - on the 50th anniversary of the 1967 referendum that approved constitutional amendments relating to the country's indigenous people.
"That would be a richly symbolic time to complete our constitution," he said.
"But I do not want it to fail because every Australian would be the loser. It is more important to get this right than to try to rush it through."
And Mr Abbott stressed: "I am prepared to sweat blood on this.
"The country we created has an Aboriginal heritage, a British foundation and a multicultural character and it's high time that this reality was reflected in our constitution."
Meanwhile, opposition leader Bill Shorten urged the referendum question to be formalised before the next general elections for the campaign to move forward.
Mr Shorten said that otherwise "it is just not possible to raise awareness (about the issue) beyond the abstract".
In 2010, the government formed an expert panel to examine constitutional recognition of Aboriginal and Torres Strait Islander peoples.
JUSTCLICK & CONNECT