YANGON, MYANMAR, SEPT. 7 -- Six leaders of the main Burmese opposition party have been arrested on charges of spying and creating unrest, the military government said today.

Kyi Maung, acting leader of the National League for Democracy, and party secretary Chit Kaing, were arrested Thursday and charged with "handing over classified state secret documents of national interest to unauthorized persons," Maj. Gen. Khin Nyunt told a news conference. He did not say what the documents were or to whom they were handed.

A Western diplomat in Bangkok said he expected the reaction of the people of Myanmar, formerly Burma, to be quick and vigorous. "All hell is going to break out," he said.

Australian Foreign Minister Gareth Evans immediately condemned the arrests, saying in a statement released by the Australian Embassy here that they "further discredited the military regime . . . and made a mockery of the national elections in May."

The league won an overwhelming 80 percent of 485 seats contested in general elections on May 27. Its leader, Aung San Suu Kyi, has been under house arrest since July 1989. Party chairman Tin Oo was jailed last December.

Kyi Maung has openly rejected the military government's timetable for a drawn-out handover of power. The league wants a new national assembly to convene this month to draft and enact a new constitution as soon as possible.

Khin Nyunt, speaking at a weekly press briefing, said four other league members were arrested in the central city of Mandalay on Aug. 8 and charged with causing unrest in that city.

Ohn Kyaing, Thein Dan, Ye Myint Aung and Sein Hla Aung had distributed antigovernment leaflets intended to create unrest, he said.

Khin Nyunt is ranked 18th officially in the ruling military council, but he is widely believed to be Myanmar's most influential leader.