A long-running joust to host a radio telescope that would give mankind its farthest peek into the Universe ended on Friday with a Solomon-like judgement to split the site between Australia and South Africa.

"We have decided on a dual site approach," said John Womersley, chairman of the board of the Square Kilometre Array (SKA) project, at a press conference in the Netherlands.

He was speaking at Amsterdam's Schiphol Airport following a meeting of the SKA organisation's members.

The two southern-hemisphere countries had been fighting fiercely to host the innovation, billed as a revolutionary giant that will be 50 times more powerful than present radio telescopes. New Zealand is included in Australia's bid.

Conceived more than two decades ago, the Square Kilometre Array aims at bringing together unprecedented size and new technology.

It would use a forest of antennae to pick up radio signals from cosmic phenomena that cannot be detected by optical telescopes.

Stars that flare into life or explode at their death, black holes, mysterious "dark energy," and relic traces of ancient events that occurred in the dawn of the Universe 14 billion years ago, are among its targets.

"Today we are a stage closer to achieving our goal of building the SKA," said Womersley in a press release.

"This hugely important step for the project allows us to progress the design and prepare for the construction phase of the telescope.

"The SKA will transform our view of the Universe; with it, we will see back to the moments after the Big Bang and discover previously unexplored parts of the cosmos."

The scheme entails linking 3,000 antennae, sited in groups along five spiral arms, progressively farther from a core array.

Put together, this creates a collection area of one square kilometre (0.4 square miles), leading to a 50-fold gain on sensitivity compared to present radio telescopes.

Building the SKA also requires unprecedented computer power. It will need the equivalent processing ability of 100 million PCs to process all the data.

The idea of the SKA was floated back in 1991, but the project has been troubled by wrangles over the site and concerns over budget.

There remain important blanks about how the two rival schemes will dovetail and whether there will be implications on timetable and cost, said analysts.

"The office of the SKA Organisation will now lead a detailed definition period to clarify the implementation," the SKA said. The assessment will take about six months.

Headquartered in Manchester, England, the SKA is a partnership of 67 organisations in 20 countries. Eight countries are full members of the consortium, including Australia and South Africa.

The two candidates were excluded from Friday's meeting on the host site, which looked at the quality of infrastructure, "the political and working environment" and whether the sites were sufficiently free of radio pollution.

"Both sites were well suited to hosting the SKA... but... they identified southern Africa as the preferred site," the press release said.

According to plans that were made for a single-site project, the first phase of the scheme would be completed by 2019 and become operational in 2020.

The second and final phase would be completed in 2024.

"The target construction cost is 1,500 million euros," or $1.87 billion at today's exchange rates, SKA said on Friday.

This figure is unchanged from previous estimates, but sources at the SKA said there are likely to be additional costs from a dual-site format.