By Nausheen Thusoo and Lewis Jackson

SYDNEY Australia's Dexus on Wednesday swung to its first net loss since 2009 as higher interest rates wiped nearly A$1.2 billion ($773.16 million) off the value of its property portfolio, in a fresh blow for the troubled real estate sector.

The property industry globally, and office building owners in particular, are struggling as home working and e-commerce lead tenants to reconsider floor space just as higher interest rates reduce building values and raise debt servicing costs.

Dexus, one of Australia's largest office landlords, delivered a net loss of A$752.7 million for the year ended June 30, down from a A$1.62 billion profit a year earlier.

The loss was driven by a A$1.18 billion valuation downgrade across its A$17.4 billion property portfolio, predominantly in the office sector, where values fell by 8.8%.

Adjusted funds from operations (AFFO), which excludes valuation changes and one-off charges, were A$555 million, down 3% from a year earlier.

Shares fell 4% at the open before rallying slightly to be down 2.8% after the first half hour.

"Operating in an uncertain economic environment remains challenging," Dexus CEO Darren Steinberg said in a statement. "In this environment we have continued to diversify our capital sources, and grow and diversify our funds management business, while we re-weight the Dexus portfolio."

Occupancy across Dexus' portfolio of 62 office properties was 95.9%. Roughly a third of tenancy renewals last financial year added floor space, versus 9% of those contracting, the company said.

Dexus continued to raise equity over the past financial year, reporting A$1.6 billion in third-party equity commitments and an oversubscribed new airport investment vehicle.

The company secured A$2.6 billion in new financing, including a A$500 million exchangeable note issue. Pro-forma gearing was 27.9%, below its 30% to 40% target range.

"Dexus has operationally outperformed the market from their higher quality portfolio, however investors will remain cautious of global office fundamentals," Citi analysts said in a note.

Dexus forecast a slightly lower AFFO in fiscal 2024, driven by a fall in trading profits.

($1 = 1.5521 Australian dollars)

(Reporting by Nausheen Thusoo in Bengaluru and Lewis Jackson in Sydney; Editing by Shilpi Majumdar and Jamie Freed)