It is the second leak from within the military acquisition project which has come down to a race between bids from French, German and Japanese companies for an A$50 billion contract to build 12 submarines.
Australia's Federal Police confirmed in a statement to the ABC that they had been asked to investigate, the broadcaster said.
Police spokesmen were not available for comment.
The investigation follows an ABC report earlier in the week that said the Japanese bid had been "all but eliminated" from the tender process.
No official announcement on the outcome of the tender has been made.
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A final decision had been expected at the end of the year but Prime Minister Malcolm Turnbull's recent gamble on a July 2 election has sped up the process and a winner is now expected to be announced by the end of the month.
The contract is politically sensitive as it will likely have an impact on thousands of jobs in the shipbuilding industry in South Australia state. Retaining votes in key electorates in that state will be critical for the government.
Mitsubishi Heavy Industries and Kawasaki Heavy Industries are offering to build a variant of Japan's Soryu submarine.
Germany's ThyssenKrupp AG's is proposing to scale up its 2000-tonne Type 214 class submarine.
France's state-controlled naval contractor DCNS has proposed a diesel-electric version of its 5000-tonne Barracuda nuclear-powered submarine.
America's Raytheon Co, which built the system for Australia's current Collins-class boats, is vying for a separate
contract for a combat system for the submarine with Lockheed Martin Corp, which supplies combat systems to the US Navy's submarine fleet.
