SYDNEY, April 24 (Reuters) - Singapore Airlines Ltd has increased its stake in Virgin Australia Holdings Ltd to 19.9 percent, buying an additional 9.9 percent of Australia's No.2 carrier for A$122.6 million ($125.77 million) from Richard Branson's Virgin Group.
Australia's airline industry has been a battleground for global airlines seeking partnerships in recent months, with Qantas Airways Ltd establishing a wide-ranging alliance with Emirates Airlines.
The move comes a day after Virgin received competition regulator approval to buy a controlling stake in Tiger Australia from Singapore Airlines' budget associate, Tiger Airways Holdings Ltd.
The deal is subject to approval from Australia's Foreign Investment Review Board.
Singapore Airlines will pay A$0.48 per share, a 5.5 percent premium to Virgin Australia's last traded price. It bought a 10 percent stake in Virgin Australia in late 2012. ($1 = 0.9748 Australian dollars) (Reporting by Lincoln Feast; Editing by Paul Tait)