registered Jardine International Motor Holdings Ltd. announced yesterday it has bought a substantial percentage of P.T. Tunas Ridean.

Hong Kong-based Jardine Motor, 75 percent owned by Bermuda-registered Jardine Matheson Holdings Ltd., acquired 25 percent of Tunas, one of Indonesia's largest independent motor vehicle dealerships.

Jardine Motor paid $28 million for the stake in Tunas, said Bloomberg business news service.

"Tunas has a good management team and an impressive track record,'' said Mr.

Anthony Nightingale, joint managing director of Jardine Motor.

"This is an opportunity for us to develop our interests in southeast Asia.'' Tunas, based in Jakarta, has a network of 39 showrooms and sells Toyota, Daihatsu, BMW, Peugeot, Fiat and Renault cars and Honda motorcycles.

For the nine months ended September 1994, Tunas posted profit of $5 million on sales of $250 million, Jardine said.

In Asia, Jardine has dealerships in Hong Kong, Macau, China and Japan.

The company also sells cars in Australia, the US, Britain and France.

Last year, Jardine boosted profit by 11.3 percent to $81.5 million from $73.2 million in 1993 thanks to rising sales of Mercedes-Benz cars in Hong Kong and strong performance from European operations.

When earnings were announced in March the company indicated it was looking for acquisitions.