Australia has hit the "on" switch of a giant radio telescope to probe the earliest period of the universe, billions of years into the past, astronomers say.

The $51 million Murchison Widefield Array telescope in remote Western Australia, a low-frequency, wide-field radio telescope able to capture a vast amount of data from the Southern Hemisphere sky, was launched by the country's Science and Research Minister Kim Carr, The Australian reported Wednesday.

The MWA is one of three "precursor" instruments for the world's most sensitive radio telescope, the Square Kilometer Array, which will link radio telescopes in Australia and southern Africa and be used by astronomers worldwide.

Detecting the formation of the first stars and galaxies is the "prime science goal" for the MWA, project director Steven Tingay of Curtin University in Perth said.

"It's a case of finding a needle in a haystack -- by the time the signal gets to us (from 13 billion years ago) it's incredibly weak," he said.

The period of interest is half a billion to one billion years after the Big Bang when proto-stars, galaxies and quasars began to emerge, he said.