NGK Insulators Ltd., the world's largest maker of insulators for power utilities, said Thursday it and India's Aditya Birla Group agreed to set up an insulator-making joint venture in Halol, north of Mumbai, in December.

The venture, Birla-NGK Pvt. Ltd., will manufacture porcelain insulators, especially substation apparatus insulators, the Nagoya-based company said.

Because NGK has been making insulators for use with power transmission and distribution apparatus at its factories in such nations as China and Indonesia, the Indian plant will enable it to provide a complete lineup of insulators at low cost on the global market, NGK officials said.

The Indian venture will use the existing production lines of the insulator business division of Indian Rayon & Industries Ltd., a part of the Aditya Birla Group, they said.

The venture will be set up after the division becomes an independent company through a separation from Indian Rayon, with NGK to acquire a 50 percent stake at a cost of $25 million, they said.

NGK envisions conducting additional capital outlays to boost production capacity and the quality of products from the Indian venture, they said.