UPDATE 1-Thai True Corp says downturn to hit 2009 revenue

* Sees 2009 revenue up less than 5 pct

* To use marketing campaign to lure customers, 3G would help

* Shares at two-week lows (Adds details, shares)

BANGKOK, Sept 28 (Reuters) - True Corporation PCL TRUE.BK, Thailand's only integrated telecoms firm, said on Monday it would not escape the effects of the economic downturn and its revenue this year would rise less than 5 percent from 2008.

Last year the company had 61 billion baht ($1.82 billion) in revenue.

"Our revenue growth this year should rise less than 5 percent because of the economic downturn, which means less customers," Chief Executive Supachai Chearavanont told reporters.

Shares in True Corp, the major shareholder of Thailand's third-largest mobile phone operator, True Move, lost 7.7 percent to 3.10 baht, its lowest since Sept. 10, at 0518 GMT. The broader index .SETI fell 1.07 percent.

The shares failed to get a lift from Thailand's telecoms regulator saying it expected a long-awaited auction for third-generation mobile phone licences to be held in the second week of December. [ID:nBKK187822]

Supachai, who said nearly 50 percent of the company's revenue came from True Move, said it would spend more money on marketing campaigns in the upcoming quarter to attract customers in a sluggish mobile phone market.

"As for True, we expect new customers to account for one-third of the expected overall market's 2-2.5 million customers," he said.

The arrival of 3G would help its non-voice business see a jump in growth, Supachai said, without giving specific forecasts.

The company has no plans to seek partners for the 3G auction but would consider having one after, Supachai said, adding several potential overseas partners had shown interest.

With the sector near saturation since almost everyone in Thailand has a mobile phone, new 3G services would allow telecom companies to tap new revenue streams by beefing up non-voice services with music, video, pictures and data. ($1= 33.58 Baht) (Reporting by Manunphattr Dhanananphorn; Writing by Ploy Ten Kate; Editing by Alan Raybould)