(Reuters) -Singapore Telecommunications posted a 5.4% rise in its first-quarter profit on Thursday, driven by strong performance in its domestic and Australian telecom operations, as well as in its IT business, sending its shares to a two-week high.

Operating earnings for its Australian telecom unit Optus rose 4.2% to S$475 million ($360.59 million), helped by price increases in postpaid plans and a higher prepaid customer base.

Optus drew attention recently over problems caused by an outage last year, as well as a massive cyber attack in 2022, which had impacted earlier profits.

Earnings from SingTel's domestic operations also rose about 4% to S$385 million.

That helped boost the telecom operator's underlying net profit to S$603 million for the three months ended June 30, from S$571 million a year earlier.

"Improvements in our core businesses in Singapore and Australia...helped mitigate lower contributions from our regional associates due mainly to significant currency headwinds in Africa," said SingTel CEO Yuen Kuan Moon.

Shares in SingTel rose more than 2%% by 0214 GMT, hitting their highest level since Aug. 1.

Southeast Asia's leading telecom firm also forecast high single- to low double-digit growth in operating earnings for the full year.

($1 = 1.3173 Singapore dollars)

(Reporting by Shivangi Lahiri and Adwitiya Srivastava in Bengaluru; Editing by Anil D'Silva)