Unionized pilots at South Korean carriers Korean Air and Asiana threatened on Wednesday to stage a strike after July 4 if demands for better working conditions were not accepted.

Demands include allowing pilots 30 hours of rest between flights and limiting flight time for Asiana pilots to less than 1,000 hours a year, the Flight Pilot Union said in a statement.

The union belongs to the militant umbrella group, the Korean Confederation of Trade Unions. It said pilots of Korean Air and Asiana would begin protests that could include a strike.

"The intensity and method of labor protests will be determined by leaders of the unions," said a Korean Air union official, adding a date for action had yet to be set.

"We believe the airlines' top policy should be placed on flight safety, not on operating profits."

The Korean Air union branch, whose members include 1,331 pilots, said more than 80 percent voted in favor of a strike.

A spokesman at Korean Air said it was regrettable the union had threatened to strike while it was in talks with management.

South Korea traditionally faces a seasonal rise in union action every summer during wage talks. But there may be little public support for the unions this year because economic growth is slowing as exports weaken and domestic demand remains patchy.