TOKYO (AP) _ The government is dismissing worries that the flood of sympathy for ailing Emperor Hirohito will trigger new demands that Japan revive its military might.

Foreign Ministry spokesman Yoshifumi Matsuda said Thursday the illness of the world's longest-reigning monarch will not create pressure to change the post-war constitution, which forbids use of military force.

''There will be no such general voices coming up towards that direction or to think about the constitution or a change of course,'' he said.

The official sought in particular to discredit what he called the ''strange opinions'' of conservative author Hideaki Kase. The writer's remarks to the Foreign Correspondents' Club of Japan last week were reported by some journalists as portending a surge of nationalism during a post-Hirohito transition.

Rightists, including some members of Parliament from the governing Liberal Democratic Party, would like to change the constitution to restore some of the emperor's traditional status and allow Japan to be more of a military power.

The 87-year-old emperor, who took power in 1926, has been bedridden since internal hemorrhaging caused him to cough up blood Sept. 19. He is being fed intravenously and has received daily blood transfusions.

Hirohito remained in stable condition today.

Rightists have worked quietly behind the scenes to increase public sympathy for Hirohito since he fell ill. The effort has been led by Shizuka Kamei, a member of Parliament and leader of the Liberal Democratic Party's Fellow Thinkers Council on Fundamental National Issues.

Kamei spearheaded the drive to set up nationwide registries for people to sign and wish Hirohito a speedy recovery.

''It's not nationalism or revisionism,'' Kamei has said. ''The emperor is like our father, and he is sick.''

Kamei is in favor of revising the constitution. Earlier this year, he and his group supported a Cabinet minister who was forced to resign for saying Japan was not an aggressor in World War II but was simply fighting to protect itself ''at a time when the white race had turned Asian into a colony.''

Leftists have criticized both Kamei and the government, saying they are creating an unwarranted mood of mourning with such things as the registries and the many cancellations of trips by Cabinet members.

Mainstream newspapers and some governing party members also have criticized the government for overreacting to Hirohito's illness. Prime Minister Noboru Takeshita has said government business should go on normally as much as possible.

Asked at Thursday's weekly briefing for foreign journalists if rightists would be able to open debate on revising the constitition in view of the outpouring of sympathy for the emperor, Matsuda replied, ''Absolutely not.''

Matsuda said the correspondents' club made a ''very great mistake'' by inviting Kase, who he said represented ''just a handful of people in Japan.''

Japan's postwar constitution, largely imposed by U.S. occupation authorities, not only forbids use of military force but also ends the emperor's role as living god and source of all political authority. The constitution now defines the emperor as ''the symbol of the state and of the unity of the people'' and gives him only ceremonial duties.

The militarists who ran the country before and during World War II invoked Hirohito as inspiration for attacks that put most of East Asia under Japanese rule.

But opinion polls consistently show the public is largely content with the emperor's symbolic role and the low level of military spending in today's Japan.