Australian Greens leader Christine Milne believes News Ltd is coming after Network Ten, claiming the Murdoch company is steadily increasing its influence within the broadcaster.
Senator Milne told parliament Ten's Sunday political program Meet the Press had been "contracted out to News Limited" and pointed to its involvement in the show's production.
She also cited the appointment of top News International executive Hamish McLennan as Ten's new boss.
The senator has now asked the Australian Communication and Media Authority (ACMA) whether News Ltd has breached Australia's concentration of media ownership rule in its dealings with Ten.
Lachlan Murdoch is chairman of Ten and is a director of News International, which is led by his father Rupert Murdoch.
Senator Milne repeated her claims in an interview with Sky News, saying "News not only owns The Australian and the tabloids, Lachlan Murdoch has the DMG radio stations around the country".
"That is an issue of getting influence in television through the back door, and that's what I'd like ACMA to look at.
"After all, Rupert owned Channel 10 and then he had to divest it when they bought up all the tabloids; having now achieved that penetration in the print media, they're now coming back for Channel 10."
Communications minister Stephen Conroy earlier told parliament if the Greens had any evidence Lachlan Murdoch had broken media rules, they should refer it to the authorities.
"As to whether or not he (Lachlan Murdoch) is influencing Channel 10, clearly as chair he has a role to play," Senator Conroy said during question time.
"But in terms of the combined interests, if the senator believes there is any matter that needs to be looked at she should refer it to the proper authorities."
Lachlan Murdoch has a number of investments in Australia through his private company Illyria Pty Ltd.
A News Ltd spokesman dismissed criticism of the company's links to the Ten Network as "conspiratorial, highly fanciful and wrong".
"News Limited has no plans to acquire Channel Ten," the spokesman said in a statement.
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