Faced with slowing growth in its traditional carrier business, Singapore Telecommunications - Southeast Asia's largest telecoms operator - has been trying to diversify for years.

But some investments such as those in digital marketer Amobee and cyber-security firm Trustwave yielded weaker-than-expected returns, forcing writedowns that largely accounted for Singtel's exceptional charges this year.

On infrastructure, CEO Yuen Kuan Moon told a briefing that options would include investing in some assets with partners and divesting others.

"Some of our assets are valued at telco multiples today, which we have the potential to be revalued at far higher multiples," said Moon, who took on the top job in January.

The company also said it is seeking partnerships and minority stakes in quick-growing regional firms in areas such as financial services and gaming, which Singtel is betting will benefit from its 5G capabilities and large client base.

Singtel, whose biggest shareholder is state investor Temasek Holdings, said annual net profit halved to S$554 million ($418 million), the lowest since at least 1998. Profit excluding exceptional items slumped 30% to S$1.73 billion.

"This is part of the kitchen-sinking exercise to give a clean slate to the new CEO," said DBS analyst Sachin Mittal.

He noted that Singtel's core business is being valued similarly to other operators that do not own infrastructure assets, which typically command higher valuations due to their regular cash flow and highly visible growth.

"This is a problem," he said.

Singtel has already begun a partial sale of its Australian subsidiary Optus' towers and expects the deal to close before year-end.

The company said it will also focus on growing its 5G enterprise and consumer business. Its information and communications technology subsidiary, NCS, will look to enterprise businesses in Singapore, Australia and Greater China to boost growth.

Singtel shares fell as much as 3.2% before paring some losses to trade 2.4% lower at S$2.4, while the broader market was up 0.7%.

($1 = 1.3236 Singapore dollars)

(Reporting by Aradhana Aravindan in Singapore; additional reporting by Anushka Trivedi in Bengaluru; editing by Richard Pullin and Sayantani Ghosh)

By Aradhana Aravindan