TACOMA, Wash. (AP) _ With work nearing completion on $46 million worth of shipping improvements on Commencement Bay, Port of Tacoma officials hope to lure more container operators like Sea-Land Service Inc.

Sea-Land, the world's largest container service, has been the Port of Seattle's biggest tenant but decided three years ago to head south. Company officials plan to occupy the new 76-acre terminal, built at a cost of $29.5 million by the port of Tacoma, on May 1.

Other improvements at Puget Sound's No. 2 port include a $10.5 million, 33- acre terminal for Totem Ocean Trailer Express and a $6 million ''intermodal railyard,'' which includes a crane to lift containers off cargo ships into a loading area and side loaders to mount them onto waiting trains.

The railyard, slated for completion in May, is aimed at eliminating trucking costs between dock and railhead. Sea-Land officials estimate their savings alone at $1 million a year.

All told, the improvements are expected to boost Tacoma's standing as a container port from 19th place to sixth or seventh place in North America and from about 69th place to 22nd place in the world.

''Tacoma is now the gateway to Alaska ... a role that has been Seattle's,'' said Blaine Johnson, director of port relations.

About 80 percent of all shipping to the 49th state is expected to be handled by Sea-Land and TOTE.

Port executive director Larry Killeen said Sea-Land's move from Seattle has put Tacoma on the world shipping map and ''into a growth cycle. It moves us into the big leagues.''

About 800 of the port's 2,400 acres are undeveloped.

''The main thing going here is the room,'' Johnson agreed. ''There's room to develop these intermodal yards and container sites on dockside. Seattle is basically locked in. It's limited by space.''

Patrick O'Malley, president of the Tacoma Port Commission, said the ''No. 1 selling point'' is the 91-car, 25-acre intermodal railyard adjacent to shipping berths. When opened, it will be the largest facility of its kind on the West Coast.

The project will bring a fast ''flow of cargo,'' with cargo from a ship arriving on Sunday from the Orient moving by rail for Chicago the next day, illeen said.

''No one on the West Coast can do that'' right at the shipping terminal, Killeen said.

The Los Angeles and Long Beach ports are building a new intermodal yard, but it is five or six miles away from dockside, forcing carriers to truck their goods through heavy traffic, Killeen said.

About 85 percent of all marine cargo arriving in Tacoma is to be shipped out by Burlington Northern or Union Pacific.