Managing director Andy Gill yesterday sent out an internal communication to staff informing them that Sunday World employees had been notified about the company's intentions.
Tiso Blackstar owns the Sunday Times, Financial Mail, Sowetan and Business Day, among other titles.
The company also shut down the print edition of The Times in 2017.
Gill said the company was “proposing a broad restructuring of its editorial operations as a result of the economic headwinds facing the business”.
He blamed looming job cuts and possible closure of the Sunday World on poor revenue.
Tiso Blackstar has also issued Section 189a notices to the editorial staff of the Sowetan, Daily Dispatch and The Herald, and editorial production staff in the business media stream.
“We are aware that the current situation is difficult, especially for those affected by restructuring, but it is important to consider the alternative future if we do not act now - one in which further title closures and widespread job losses become inevitable,” Gill said.
SA National Editors’ Forum chairperson Mahlatse Mahlase expressed concern over the looming job losses.
"The retrenchments come at a time when the industry has been shedding jobs at an alarming rate, which is very concerning.
"Newsrooms are becoming smaller, and that will always have an impact on the quality of journalism and diversity in the media," she said.
The announcement comes at a time when some employees were on a strike which started last week after negotiations over pay, lack of bonuses and working conditions for journalists collapsed.
Yesterday, the employees picketed outside the group's offices at The Hill on Empire Road in Joburg.