Paul Armstrong, the controversial editor of The West Australian newspaper, is no longer employed by the paper, the ABC has reported.
Newly installed chief editor Bob Cronin has become the acting editor after breaking the news to staff yesterday, reports have said.
West Australian Newspaper Holdings has reportedly said the split was a mutual agreement.
Seven Network chairman Kerry Stokes gained control of the WAN board after three board members resigned last year amid the newspaper's falling share price.
Since representatives of Seven took key seats on WAN's board, speculation has been rife that Mr Stokes would move to replace Mr Armstrong.
The media mogul has been critical of Mr Armstrong's controversial editorial approach.
Seven holds a 22.3 per cent stake in WAN.
Mr Cronin, a colleague of Mr Stokes, was appointed editor-in-chief on December 15.
He played a senior role at Mr Stokes' Shanghai Daily newspaper in China for several years.
In December, Mr Stokes said the future of Mr Armstrong was in the hands of WAN's chief executive Chris Wharton.
Mr Stoke's first move as chairman was to appoint Mr Wharton, former managing director of Seven Network's Perth television station, as chief executive.
Mr Wharton replaced fellow former journalist Ken Steinke, who resigned as chief executive and managing director.
WAN was up three cents, or 0.42 per cent, at $4.77 at 1014 AEDT.
