Optus chief executive Stephen Rue says he will keep a tight lid on costs to improve profit margins at the Singaporean-owned telco group, after annual earnings rebounded following last year’s hefty write-downs.

“We need to manage our costs very judiciously,” Rue told The Australian Financial Review, adding Optus aimed to keep increasing its profit margins from the 27.2 per cent reported in the 12 months to March 31.