By Rob Taylor

CANBERRA (Reuters) - Australian Prime Minister Kevin Rudd's apology to Aborigines for past injustices has been turned into a song, with rights activists on Monday saying the apology was a defining national moment.

"Some moments in a nation's history are so significant, so uplifting and so unifying they become the inspiration for artists, thinkers and dreamers," said Brett Solomon, from the political activist group GetUp.

"They turn those moments into the food which nourishes the nation's soul," Solomon said.

Rudd, whose centre-left government swept away almost 12 years of conservative rule in November, apologised in parliament to Aborigines on Feb.13, saying past assimilation policies since British colonisation were wrong.

Rudd's words feature at the start of the song, which adapts a hit ballad "From Little Things, Big Things Grow" by singer Paul Kelly, which told of an eight-year strike by Aboriginal stockmen that led to formal recognition of indigenous land rights.

A video clip at www.getup.org.au features Aboriginal elders and Rudd's address, while vocalists sing "they're not only words, it's not just a symbol" against grainy historic images of Aborigines in orphanages and work parties.

"We can't face the future now until we face the sorrow. We're saying never forget, we're saying no turning back," the song, launched by Australia's Arts Minister and former rock star Peter Garrett, continues.

The singers include some of Australia's biggest music stars including Kelly, Missy Higgins and Hip-Hop artist Tim Levinson, known in Australia as "Urthboy".