Northwest Airlines Inc. yesterday announced plans to acquire 25 percent of Hawaiian Airlines as part of a $20 million deal that will give Northwest the rights to fly the Hawaiian carrier's Australia route.

Analysts said that the move appeared to be part of an effort to expand Northwest's strong presence in lucrative Asian markets into the South Pacific.

Northwest already provides service from Honolulu to other destinations in the Far East and to the West Coast.

"Obviously it's to get to Australia," said Robert J. Joedicke, an analyst with Shearson Lehman Brothers Inc. in New York.

United Airlines and Continental Airlines, which have also expanded their Pacific service, already fly to Australia.

Joedicke also said the deal is typical of the trend among airlines to expand internationally through equity swaps and joint marketing arrangements.

The $20 million that Northwest, the nation's fourth-largest carrier, will pay Hawaiian and its parent HAL Inc. includes a $7 million secured loan.

The agreement calls for the two airlines to cooperate in marketing and operations, and it includes provisions under which Northwest will lease two wide-body jets operated by Northwest pilots to Hawaiian.

Hawaiian will also transfer its route authority to fly between Guam and Saipan, in the Northern Marianas islands, and between Nagoya and Fukuoka, in Japan, to Northwest.