Optus will cut 350 jobs from its workforce in the next four weeks in an effort to improve sustained profitability and increase efficiencies.
The company said it would consolidate roles in a number of corporate functions while some other positions would become redundant
"Optus must continually review its operations to ensure we remain sustainable and competitive in the years ahead," the company said in a statement on Wednesday.
Australia's second largest telco has already reduced staff numbers; over the nine months to December 31, 2013, it had an average of 8,685 employees, down from 9,130 in the same period a year earlier.
Those changes have recently delivered profit growth, with the company making a net profit of AU$722 million in the nine months to December 31, up from AU$480 million in the same period a year earlier.
CWU national assistant secretary Ken Hardisty said he hoped it was the last round of job cuts at Optus.
"Fortunately the numbers (this time) haven't been as high, which is some consolation I suppose," he said.
"At this stage you'd hope there would be nothing after this, the objective has been achieved of putting them on the right foot they're looking for.
"But obviously we'll be looking at protecting as many members jobs, that we can or be redeployed and suitable arrangements can be made."
The Optus spokeswoman declined to rule out further jobs cuts, and said that improving efficiencies was an ongoing process.
"Part of that strategy is about re-engineering our business for the future and this is one of a number of initiatives that we are putting in place," the spokesperson said.
"Over an 18-month period we have done a number of these to restructure and refocus the business around customer service."
Hardisty said it did not appear that too many Optus jobs were being moved offshore.
"There is a small offshoring component which affects the about a maximum of 12 positions," he said.
"They've advised us that they've found duplication of functions and centralised them into one location, so there's been a bit of reorganisation and rebalancing of the resources."