A Brooklyn federal judge yesterday handed down an unorthodox decision, ordering the Mets to allow a kosher-food vendor to sell its fare at Citi Field on the Jewish Sabbath.

Kosher Sports, which sells its blessed hot dogs, knishes and peanuts at the ballpark, sued the Mets in federal court last month, claiming it lost half a million dollars when it was prevented from selling food Friday nights and Saturday.

The Mets’ lawyer argued that selling or buying kosher food on Friday nights or Saturday is a contradiction in terms, but the judge declined to take a side.

“I cannot get involved in a dispute over rabbinical law,” said US District Court Judge Jack Weinstein.

The Mets say that they didn’t violate the contract with Kosher Sports — that Aramark, another food-concession company, did.

Aramark has refused to supply the kosher vendor with carts for Friday nights and Saturdays, the Mets said.

The ballclub countersued the kosher company, claiming the Mets were owed $650,000 for the right to sell wares at the games.

The judge ordered the two sides to work out the terms of the agreement among themselves.