WAILUKU, Maui — The Hawai'i Superferry will remain on course for a launch in early 2007 now that a Maui judge has thrown out a lawsuit by the Sierra Club and two other groups, a company official said yesterday.

The Sierra Club, Maui Tomorrow and the Kahului Harbor Coalition had demanded that the interisland ferry undergo a full and lengthy environmental review before starting up.

However, 2nd Circuit Judge Joseph Cardoza ruled yesterday the groups had no standing to bring the lawsuit, and that the state and the Hawai'i Superferry properly followed environmental law.

John Garibaldi, Hawai'i Superferry Inc. chief executive, hailed the ruling as a "significant milestone" that will permit the company to complete financing arrangements and construction of its first ship. He also called it a victory for Hawai'i residents interested in a less-expensive alternative to air travel.

Isaac Hall, attorney for plaintiffs, said he would recommend an appeal of Cardoza's ruling, and that the groups might explore whether the state violated any federal statutes aimed at protecting endangered species.

"The citizens of Maui are entitled to more environmental review," he said.

Some of the concerns include increased traffic on already crowded roads, the proliferation of island-hopping alien species, threats to humpback whales and an influx of fishermen from other islands seeking new and easy access to fishing areas.

The lawsuit was filed in March in an effort to force the state Department of Transportation and Hawai'i Superferry to conduct a study of the operation's potential environmental impacts. Such studies are usually required on projects involving substantial spending and major construction.

The state Legislature this year approved a $40 million expenditure for harbor improvements to accommodate the ferry. At Kahului Harbor alone, the state is planning to buy a $10 million barge and install fencing, among other things.

In the lawsuit, the plaintiffs asked that Hawai'i Superferry be prohibited from implementing any segment of the project and the state be prohibited from granting any approvals until an environmental impact statement, or at the very least, an environmental assessment, is done. They said the scale of the project requires such a study.

The state and Hawai'i Superferry filed motions to dismiss the suit, and Cardoza complied, without elaborating.

Bill Wynhoff, state deputy attorney general, argued the DOT granted the company an exemption to Chapter 343, a Hawai'i environmental law, because the harbor improvements were considered ancillary to existing structures. Transportation officials have said the planned improvements would not require dredging, permanent facilities or waterside construction.

The environmental law isn't triggered every time a new shipping company plans to use a harbor, Wynhoff said, and the same reasoning should apply in this instance.

Nevertheless, county councils on Maui, Kaua'i and the Big Island approved resolutions calling for an environmental impact statement for the ferry system. A similar bill in the state Legislature failed.

Garibaldi said the Superferry project remains on course for its 2007 debut, although it appears the Legislature's two-year financing plan for harbor improvements will allow initial service only to Honolulu, Maui and Kaua'i. The Big Island's Kawaihae Harbor will be added a year later.

One-way fares between Honolulu and the Neighbor Islands are expected to range from $42 to $62, with one-way fees for cars ranging from $55 to $75.