An Indian national accused of spying on Sikh and Kashmiri communities in Germany for New Delhi's secret services went on trial in Frankfurt on Tuesday.

The suspect, identified as 54-year-old Balvir S., is accused of working for the Research and Analysis Wing (RAW), India's foreign intelligence agency, from at least January 2015.

Prosecutors say he "obtained information about figures in the Sikh opposition scene and the Kashmiri movement and their relatives in Germany, and passed this on to his handlers who were working at the Indian consulate general in Frankfurt".

A total of 10 hearings before the regional superior court are scheduled, with the trial due to conclude on October 29.

The same Frankfurt court convicted an Indian couple for spying on the same communities last December. The husband was handed a suspended prison sentence of 18 months for acting as a foreign intelligence agent and his wife fined 180 days' wages for aiding him. 

India and Pakistan have disputed Kashmir since they became independent and split in 1947, with the nuclear rivals fighting two out of three wars over the region. An insurgency against Indian rule has been waged since 1989 in Kashmir, claiming tens of thousands of lives.

Frankfurt is of particular interest to the Indian secret services because western Germany is home to the largest Sikh community in the country, estimated at between 10,000 and 20,000 people, and one of the largest in Europe.