April 18 (Reuters) - Holtec International, which is in charge of decommissioning the Indian Point nuclear power plant in New York, on Thursday filed a lawsuit against the state over its rules regarding the discharge of radioactive materials from nuclear power plants.

The company said the authority to monitor radioactive discharge was with the U.S. Nuclear Regulatory Commission (NRC) and not the state of New York.

The state in 2023 passed a law that makes it unlawful to move "any radiological substance into the Hudson River in connection with the decommissioning of a nuclear power plant."

"The passage of the bill has already delayed the planned completion of the decommissioning of Indian Point an additional eight years...we look forward to the legal process moving along on this important decision," the company said in its lawsuit in the Southern District Court of New York.

"The failure of New York State to respect Federal Law, and follow the facts and science of the issue, left us no other means for remedy," a Holtec spokesperson said.

New York's law would lead to Holtec having to "choose an alternative method of disposal for tritiated water...even if the discharge of the tritiated water to the Hudson River would meet the NRC's regulations," the filing said.

The alternative method could likely add to the costs of the decommissioning.

New York's concerns about Indian Point's practice of storing spent nuclear fuel in densely packed cooling pools played a significant role in the facility's closure in 2021.

Separately, the Indian Point Decommissioning Oversight Board, which is led by New York's Department of Public Service, said while it would forego the discussion, it plans to continue presenting alternative methods of wastewater removal next week.

(Reporting by Seher Dareen in Bengaluru; Editing by Sriraj Kalluvila)