UPDATE 1-Australia, U.S. strike open-skies pact

(Updates with Qantas reaction, analyst)

By Rob Taylor

CANBERRA, Feb 15 (Reuters) - Australia and the United States have agreed to open up trans-Pacific air routes between the two countries, prompting Australia's Qantas Airways Ltd (QAN.AX: Quote, Profile, Research, Stock Buzz) on Friday to immediately increase its flights.

Australia's Transport Minister, Anthony Albanese, said talks with U.S. officials in Washington had reached agreement on an open-skies pact, which could see more U.S. carriers fly to Australia via ports in Asia, such as Tokyo.

"This agreement will remove restrictions on competition for the benefits of Australian jobs and consumers," Albanese said in a statement.

The deal helps clear the way for Australian airline Virgin Blue Holdings Ltd (VBA.AX: Quote, Profile, Research, Stock Buzz) to begin flights to the United States on its carrier V Australia by the end of this year, edging open one of the world's most lucrative and protected long-haul routes.

But shares in Australia's flag-carrier Qantas slumped by 4.6 percent to A$4.53 at 0352 GMT on expectations the airline will face tougher competition on the prized cross-Pacific leg, on which it has a near-monopoly.

Qantas chief executive Geoff Dixon said the airline welcomed more competition and would add three extra flights from March.

"It brings new opportunities for growth and competition. Importantly, it will assist the further development of Australia's aviation industry, as well as help increase trade and tourism with a major economic partner," Dixon said.