SEOUL, SOUTH KOREA, NOV. 26 -- Hyundai Motor Co. said today it will make an all-out effort to reverse a Canadian ruling that the South Korean auto maker is guilty of dumping.

Acting on complaints from the Canadian subsidiaries of General Motors Corp. and Ford Motor Co., authorities in Canada on Tuesday ordered Hyundai to pay an average of 36 percent duty per car or post a bond covering that amount, pending a final ruling by the Canadian Import Tribunal.

In international trade, dumping refers to the practice of selling products abroad below cost to gain an edge over competition.

Hyundai officials in Seoul said the auto maker will seek to overturn the dumping charge before the tribunal issues a final ruling, due within 90 days.

The officials said the preliminary ruling relied on allegations by the General Motors and Ford Motor subsidiaries while dismissing data presented previously by Hyundai as untrustworthy.

The Hyundai officials said they were confident that the dumping rate could be modified in the course of review.

Unless the rate is lowered, officials said, Hyundai could not export cars to Canada because its prices would go up too much.

They also feared that if penalties were upheld in Canada, the two U.S. auto giants might launch similar moves against Hyundai in the United States. There Hyundai, Korea's biggest auto exporter, has made impressive inroads since beginning sales early last year. Hyundai sold 167,000 cars in the United States in 1986.

General Motors and Ford are competing against Hyundai for the U.S. small car market. The American automakers market small cars supplied by two Korean automakers -- Daewoo Motor Co. and Kia Motors Co. -- in the United States. General Motors holds a 50 percent share of Daewoo and Ford owns 10 percent of Kia.

Officials at the Trade and Industry Ministry said the government hopes that Canada reviews the Hyundai dumping charge favorably so that the duty could be eased drastically.

Hyundai sold 79,000 cars in 1985, accounting for a 7 percent market share in Canada. That slipped to 66,100 cars in 1986