An underused dockyard at Malaysia's premier port is being upgraded in what management sees as a way to increase revenue.

"It is expected much of the business for the dockyard will come from the government and the fishing industry," said Elias Kadir, managing director of Kelang Port Management. Port Kelang serves the capital, Kuala Lumpur.The privately run management firm expects to spend US$1 million for the initial improvement work at the South Port site. Mr. Elias said this would involve servicing, repairs, refurbishing and conversion work.

He identified several potential clients, including Petronas, the Malaysian state energy monopoly; the ports of Johore and Kuantan; and the armed forces, customs and marine departments. The facility also could aid the deep-sea fishing industry with repairs, he said.

The yard, on an 8-acre site, was built by the former state-run port authority for maintenance of harbor craft. It has five slipways able to accommodate ships up to 450 deadweight tons, in addition to a 100-foot jetty, a 3-ton mobile crane and various workshops.

Mr. Elias didn't give specifics of the upgrade, but said the yard will be developed into a ship- and boat-building facility. The facility's potential ''has not been fully tapped," he said.

KPM, as the management company is known, opened the port's second container complex in August, called Kelang Port Container Terminal. A multimillion- dollar project, it competes with Kelang Container Terminal, which also is privately run.

Mr. Elias said the terminal berthed nine ships in its first few weeks of operation, producing the equivalent of 900 20-foot containers, or TEUs. The company is forecasting 150,000 TEUs in 1994, its first full year.

"We expect the volume to increase with the arrival of five rubber-tired gantries and a stacker next month and two straddle carriers in December," Mr. Elias said.

Seven straddle carriers, 21 prime movers and 27 trailers were in place for the opening. The terminal has three post-Panamax cranes, five gantry cranes and one stacker for five boxes.

It also has storage capacity for 12,000 TEUs and for 90 refrigerated boxes. That space will be increased when more land is reclaimed in 1995.

The established Kelang Container Terminal handled 677,678 TEUs last year, an increase of 12 percent on the 1991 level. It is forecasting a further 12 percent rise this year to 762,000 TEUs.