Japan Airlines said on Monday that four of its unions may hold a one-day strike on Wednesday, which could force it to cancel a quarter of its domestic flights.

The loss-making airline, at odds with the unions over wage cuts, summer bonuses and working conditions, said its international flights would operate normally even if the strike goes ahead.

JAL said if the four unions representing nearly 2,700 of its cockpit, cabin and ground staff strike, it would have to cancel up to 152 domestic flights, or 24 percent of the 646 flights scheduled for the day.

That would affect some 13,000 customers and could lead to about JPY200 million yen (USD$1.73 million) in lost revenue, it said.

A strike would be the latest bad news for JAL, which lost JPY47 billion (USD$407.2 million) in the business year ended March, hit by high oil costs and safety lapses that led some travellers to choose All Nippon Airways and other competitors instead.

JAL said in March that it had reached an agreement with JALFIO, the largest of its nine unions with over 10,000 members, to reduce wages by an average of 10 percent from April, but some unions are still opposing the cuts.

A JAL spokesman said the four unions threatening a strike were also likely upset over the size of summer bonuses and working conditions related to the planned integration of its international and domestic flight operations in October.

He said management would continue to negotiate with the unions in hopes of averting a strike.

Fukuko Torikai, a member of the JAL Cabin Attendant's Union, said the union was dissatisfied with working conditions and the wage cut and wanted management to put more resources towards safety.