* Bids total 119 bln baht vs 80.8 bln baht in 1st auction
* New licences to help secure operators' long-term growth
* Jasmine fights hard to enter mobile market - analysts
* Telecoms shares fall for second day amid pricing concerns (Adds latest bids)
By Khettiya Jittapong and Manunphattr Dhanananphorn
BANGKOK, Dec 17 (Reuters) - Thailand's telecoms regulator extended an auction for two 4G mobile broadband network licences for a third day on Thursday amid fierce competition which has raised the overall bidding to $3.3 billion, beating the total price paid for a previously awarded set of licences.
In the second auction, market leader Advanced Info Service (AIS) and third-ranked True Corp, winners in the first sale in November, are vying with second-ranked Total Access Communication Pcl (TAC) and fixed line telecoms services provider Jasmine International.
Shares in the four companies fell back for the second day in a row after a surge on Tuesday as investors worried about the high prices which are now expected to be paid in the auction.
The auction is seen as a key step in supporting the digital economy policy of the military government, which is expected to raise $5.5 billion from the two sets of auctions.
Total bids stood at 119 billion baht ($3.3 billion), with 58.27 billion baht for the first licence on offer and 60.84 billion baht for the second.
Telecoms operators want to win licences to stay competitive and make sure they have enough bandwidth to go on to offer so-called fifth-generation (5G) mobile services which should be launched in 2020, Settapong Malisuwan, vice chairman of the regulator said.
The four bidders have been supported by foreign partners, Settapong said, adding Jasmine has joined with an unidentified South Korean company.
AIS is 23 percent-owned by Singapore Telecommunications Ltd , while TAC is controlled by Norway's Telenor. True is 18 percent-owned by China Mobile.
Analysts said the fierce competition indicated that Jasmine, which does not have a mobile operation, needed a licence to secure future growth, while True and AIS were keen to prevent another company from competing for market share.
AIS shares closed down 1.7 percent, while TAC was off 7 percent, extending a 7 percent decline on Wednesday.
True Corp shares fell 3.3 percent, while Jasmine slipped 4 percent. The main Thai index was 0.86 percent higher.
To give more financial flexibility to bidders, the regulator has offered to allow winners in the second auction to pay the bulk of the licence fee in the fourth year of operation, the regulator said.
Winners in the November auction are required to pay half of their successful bidding offers within 90 days of winning the licences. ($1 = 36.1100 baht) (Additional reporting by Aukkarapon Niyomyat and Amy Sawitta Lefevre; Editing by Simon Webb and Kenneth Maxwell)