UPDATE 1-China Unicom H1 profit skids to 16-year low on hefty 4G expenses

* H1 net profit 1.43 bln yuan vs 6.99 bln yuan year-ago

* Interim profit at lowest since 2000

* Profit turnaround expected next year - chairman

HONG KONG, Aug 17 (Reuters) - China Unicom Hong Kong Ltd’s first-half net profit plunged 80 percent to a 16-year low, as China’s second-largest telecom service provider racked up heavy expenses to market its fourth-generation (4G) network.

In a securities filing on Wednesday, the company said net profit tumbled to 1.43 billion yuan ($215.67 million) for the six months ended June, matching a preliminary estimate released in July. That was down from 6.99 billion yuan a year earlier and is China Unicom’s lowest interim profit since 2000.

Revenue edged down 3.1 percent to 140.26 billion yuan from a year earlier.

China Unicom chairman Wang Xiaochu told an earnings briefing that he is expecting a profit turnaround next year after recording a net profit decline last year for the first time since 2010.

“We expect a sales turnaround in November and December, and a profit turnaround next year,” Wang said.

Competition from popular free internet-based messaging services, such as Tencent Holdings Ltd’s WeChat, continue to eat away revenue from network providers’ once-lucrative voice calls and short messaging services.

With subscribers to more lucrative, data-heavy 4G service accounting for less than a third of China Unicom’s customer base, analysts expect both revenue and costs to grow next year as it seeks to catch up with bigger rival China Mobile Ltd and smaller China Telecom Corp Ltd in building its 4G network.

“China Unicom will have to recoup lost ground and accelerate 4G rollout,” Jefferies analyst Elaine Lai wrote in a note prior to the results. “It has to catch up in 2017, but that means higher selling and marketing expenses as well.” (Reporting by Yimou Lee and Tris Pan; Editing by Kenneth Maxwell and Muralikumar Anantharaman)