"Huge value" in staying in oneworld
BA has joined the talks between American Airlines and Japan Airlines.
The UK national carrier confirmed it was working with AA and other oneworld carriers to persuade JAL to stay in the alliance.
The loss making Japanese carrier is seeking a cash injection and is also in talks with Delta Air Lines, a member of rival alliance SkyTeam.
Oneworld carriers fear that if Delta wins the battle to invest in JAL, the Japanese carrier may defect to SkyTeam, leaving it without a major Far East partner.
In a statement, BA said: "We don't comment on rumour or speculation.
"However there is a huge value for Japanese Airlines in being in oneworld.
"We are working with American Airlines and other oneworld carriers to demonstrate that to them."
BA declined to say whether it was prepared to invest in JAL.
JAL's restructuring plan under which it said it would shed 6,800 jobs, cut international routes and seek cash injections was thrown in doubt by the incoming Japanese government.
The new Democratic Party government, which has taken over from the Liberal Democratic Party (LDP), said it planned to review its predecessor's policies.
The LDP had given JAL a loan of $1.1bn earlier this year to help it with its deficit.
JAL had also been hoping for a fresh loan from the government of about $1.2bn.
But Reuters reported that the new transport secretary Seiji Maehara said he "would like to go back to the drawing board" with the panel the old government set up to deal with JAL's problems.
He said: "I would like to hear advice from a variety of viewpoints regarding Japan's aviation policy" adding that he wanted to "take a thorough look at whether the plan to restructure JAL can realistically be implemented."
The airline lost $692m last year and announced a $1bn loss for the quarter to June this year.
It is heading for a deficit of $700m for the financial year ending next March.
In its talks with American and Delta, it is seeking a cash investment of about $300m.
JAL's president Haruka Nishimatsu said it would make a choice between possible investors by mid-October.
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