The Maritime Administration rejected a $45 million check Friday from Cabot LNG Corp. for the purchase of three liquefied natural gas tankers, a company official said.

"They sent it back," R. Gordon Shearer, president of Cabot, said of the check, which totaled the amount his company initially bid on the Arzew, Gamma and Southern.Marad attorneys handling the case could not be reached for comment on the rejection Friday. The decision suggests that Marad intends to start from scratch on the bidding process, but Mr. Shearer said Cabot attorneys will ask a federal judge to prevent the agency from doing that.

Cabot, based in Boston, already has a lawsuit pending that challenges Marad's earlier decision to sell the vessels to three subsidiaries of Argent Group Ltd., New York City, for a total of $36 million, or $12 million apiece.

As a result of the lawsuit, Marad recently reversed its decision to complete that sale and said that the three potential buyers - Argent Marine I, Argent Marine II and Argent Marine III - do not meet U.S. citizenship requirements. The Argent companies had agreed to lease the vessels to Shell International Petroleum Co., London, for a fast-developing Nigerian liquefied natural gas project.

Marad found that Shell, a foreign company, controlled the three Argent companies.

Marad opened the bidding process on the three ships in October 1987. Shell attempted to bid directly on the vessels but was rejected as a non-U.S. citizen. Argent and Cabot were the only other bidders.

Cabot, a subsidiary of Distrigas Boston, argued that as the only other bidder for the ships, it should now be allowed to negotiate the sale with Marad.

Another company that is interested in the vessels, Energy Transportation Group, New York, filed a document with the court offering $80 million for each vessel. The company said a new ship would cost as much as $250 million.

Shell officials in New York City said Friday they were not aware of any immediate plans for legal action by the company. The energy giant last week voiced surprise and "dismay" over Marad's decision to reverse the decision to sell the ships to the Argent companies.