Feb 12 (Reuters) - Singapore Telecommunications reported a 9.5% rise in its third-quarter underlying net profit on Thursday, driven by strong contributions from India's Bharti Airtel and Thailand's Advanced Info Service (AIS).

SingTel reported an underlying net profit of S$744 million ($589.77 million) for the three-month period ended December 31, compared with S$680 million a year earlier.

Contributions from regional associates' post-tax profits rose more than 15% to S$529 million, led by Airtel and AIS.

SingTel also booked a net exceptional gain of S$1.15 billion from selling a 0.8% stake in Airtel as part of an asset‑restructuring plan.

That boosted its net profit on a statutory basis by 44% to S$1.89 billion.

SingTel-owned Optus, Australia's no. 2 telecom firm, reported a 5% rise in operating earnings for the quarter. That, along with robust growth in its information technology services division, NCS, helped offset weaker performance by its domestic business.

($1 = 1.2615 Singapore dollars)