SYDNEY (AFP) - The Australian government's plan to apologise to Aborigines for past injustices ran into trouble Thursday when the opposition indicated it might not support the move.

The failure of white Australia to speak with a united voice on the sensitive issue would weaken the attempt to heal the nation's racial rift, Indigenous Affairs Minister Jenny Macklin warned.

"We think this is very important to enable all of us, indigenous and non-indigenous Australians, to move forward," Macklin told reporters.

"And to move forward we really do need the in-principle support of all parliamentarians across the political spectrum."

Prime Minister Kevin Rudd plans to formally apologise for the so-called "stolen generation" of Aboriginal children taken from their parents as the first item of business of the new parliament on February 13.

Tens of thousands of children, mostly of mixed descent, were forcibly taken to be raised in white foster families or institutions under a policy of cultural assimilation officially scrapped in 1969.

The leader of the opposition Liberal Party, Brendan Nelson, has questioned whether Australians living now can take responsibility for injustices perpetrated in the past.

"The question for me is, can our generation be responsible for that?" Nelson said in a radio interview.

The removals were carried out "in most cases with good intentions, but certainly not in all," he added, arguing that many children were removed from neglect and abuse.

Nelson said he also wanted to see the precise wording of the apology, which has long been sought by Aboriginal groups and their supporters, before agreeing to back it.

The former leader of Nelson's party, John Howard, refused to make the apology during his 11 years as prime minister before being ousted by Rudd and the centre-left Labor Party in November elections.

Rudd's government has said the apology will not be backed by financial compensation, despite demands by some Aboriginal groups for hundreds of millions of dollars in reparations.

"This is not about compensation, this is about offering an apology for the things that have happened in the past, particularly to the members of the stolen generation," Deputy Prime Mininister Julia Gillard said Thursday.

The government has said it will instead invest in improved health and education services for Aborigines, many of whom live marginalised lives in impoverished communities.