* Tankers bought as N.Korea arms itself, regional tensions
* Total programme worth about 1.49 trillion won (Adds Boeing comment)
SEOUL, June 30 (Reuters) - South Korea's state-run weapons buyer on Tuesday chose Airbus Group SE to supply four in-flight refuelling tankers, a deal two people with direct knowledge of the matter said was worth around 1.2 trillion won ($1.07 billion).
The purchase of the country's first aerial refuelling tankers is part of South Korea's efforts to strengthen its air defences amid tensions between China and Japan over maritime interests and as unpredictable neighbour North Korea continues to bolster its arsenal.
Airbus' A330 MRTT beat Boeing Co's KC-46A and Israel Aerospace Industries' MMTT for the tender, the Defense Acquisition Program Administration said.
The people declined to be identified as they were not authorised to discuss the terms of the deal with the media.
The tankers are expected to be delivered between 2018-2019.
Including ground facilities and parts that will be built by South Korean firms, the entire programme will be worth around 1.49 trillion won, the people said.
Boeing said it was disappointed by the decision, which analysts called a big setback given the company's efforts to find more buyers for the KC-46 tanker it is building for the U.S. Air Force.
"While we are disappointed with this decision, we remain committed to our partnerships in Korea," the company said in a brief statement.
Airbus has been chosen to supply around 60 A330 MRTT tankers to about 10 countries including the U.K., Australia, Saudi Arabia and Singapore, with 24 tankers already in service. ($1 = 1,122.3000 won) (Reporting by Joyce Lee in Seoul; additional reporting by Andrea Shalal in Washington; Editing by Miral Fahmy and Alan Crosby)