How an Indian film idol upstages Mrs. Gandhi

It's an extraordinary campaign poster. N.T. Rama Rao, an Indian film idol turned politician, holds the gold miter of the Hindu gods. He wears a gold-embossed breastplate and jeweled crown. His eyes are dwarfed by heavy coal makeup of classic theater.

It is not merely a picture of a candidate seeking office in an important Indian election on Jan. 5. The poster for millions of voters is of the Hindu god Krishna, indeed believed to be reincarnate in the film-star image of Rama Rao.

In the harsh world of Andhra Pradesh, a poor and undeveloped south Indian state, cinema is a panacea, where illusions, without effort, form reality.

Nandamuri Taraka Ramao Rao - fondly called N. T. R. by his fans - has become part of that pantheon of Hindu gods whom he has brought into the hot, dusty cinemas of southern India in nearly 300 films.

His unorthodox style of campaigning; his disruption of the usual norms of caste; his near mythological proportions have added a sense of drama to an otherwise lackluster political fight. He has forced Prime Minister Indira Gandhi , whose party has never lost in Andhra Pradesh, out to the hustings 10 to 12 hours per day. If his new political party wins a majority in the southern state, Rama Rao will become its chief minister.

He has spawned defections in her ruling Congress-I Party. (The I stands for Indira, not India, as her opposition is quick to say.)

But beneath the glamour and the star appeal lies what political pundits see as a worrisome trend: Regionalism is challenging national politics in India, and emerging as a powerful force.

The battle will be fought Wednesday on the Deccan Plateau in the south, and in the remote northeast tribal tracts of India.

Voters will elect state assemblies in Tripura, Karnataka, and Andhra Pradesh in what will be Mrs. Gandhi's last big election test prior to the 1984 general elections.

''It is the very nature of Mrs. Gandhi,'' said one diplomatic official, ''that has permitted an N.T.R. to emerge. He is the result of two growing factors on the Indian political scene: an emphasis on regionalism and an emphasis on personality.''

Although it is assumed that Tripura will remain in the hands of Marxists, and Karnataka within the Congress-I, the Andhra contest has become a referendum on Mrs. Gandhi's concept of centralized government and her personalized politics.

So personalized is Mrs. Gandhi's style, that the slogan ''Indira is India and India is Indira'' permeates much of the countryside. Congress-I officials don't quarrel with that statement. She is the party, and her charisma returns scores of often lackluster politicians to power, election after election.

In Andhra, N.T. Rama Rao is drawing crowds unprecedented in the state's political history. He has charged that the ''dignity'' of Andhra is being damaged in far-off New Delhi, which has appointed revolving-door chief ministers. (The state has had four chief ministers in the last 25 months.)

Rama Rao's Telugu Desam (Land of the Telugu) Party, which he formed only seven months ago, says that it will offer government without corruption, provide lunches to children at school, and sell rice at subsidized prices.

It would also - and herein lies the potential danger, according to political observers here - revive the local Telugu language and culture, and resurrect ''wounded Telugu pride.'' Such admonitions in a country with 15 official languages, five major religions, and countless ethnic groups can only aggravate already serious regional strains, in the view of some diplomatic sources.

Mrs. Ghandi has been attacking Rama Rao with a stridency not present in earlier campaigns. She has warned against regionalism and injected the caste issue.

N.T.R. is a Kamma, a fairly wealthy class, concentrated in the coastal plains of Andhra. The Reddys, a contiguous caste, have held power under the Congress banner there. By subtle implication, Rama Rao, according to Mrs. Gandhi, is tampering with the distribution of power among castes.

To his millions of fans it may make a difference. But, again, it may not. It was said earlier that he had no organization, therefore no threat. But, today, hundreds of thousands of campaign workers have fanned out into the countryside - all N.T.R. fan club members. They are making an impact.