The Federal Court has told Ottawa to reimburse a First Nations band for the costs of taking care of a severely disabled teenager living at home - a ruling that could have widespread implications for federal social services on reserves.

Justice Leonard Mandamin has ruled that the federal government was wrong to cover only a fraction of the costs of taking care of Jeremy Meawasige from the Pictou Landing band in Nova Scotia.

The ruling says Ottawa is obliged to uphold Jordan's Principle  - an agreement that First Nations children should get the public help they need, regardless of jurisdictional disputes between governments about who should pay.

The principle is named after a boy who died in hospital in Manitoba while governments bickered about payment of home-care services.

Paul Champ, the lawyer for Jeremy's mother, said the ruling sets a precedent ensuring all First Nations children across Canada have access to the same level of essential government services as off-reserve children.