ST. JOHN'S, N.L. - Lawyers will argue in the Supreme Court of Canada today that a decades-old power deal they say unfairly benefits Quebec over Newfoundland and Labrador should be reopened.

Lawyer Doug Mitchell says the contract for the Churchill Falls hydro station in Labrador should be renegotiated to reflect different circumstances.

He says the arrangement has so far generated more than 27.5 billion dollars for Hydro-Quebec, versus about two billion dollars for Newfoundland and Labrador.

Mitchell says negotiators in 1969 could not have foreseen how energy markets would shift, allowing Hydro-Quebec to buy that power at cheap fixed prices then sell it for huge profits.

At issue is whether partners in long-term deals are obligated by so-called good faith principles to adjust terms over time.

Hydro-Quebec says it helped finance Churchill Falls in exchange for price guarantees that don't expire until 2041.

Newfoundland's natural resources minister says a win could mean billions of dollars for the province as it faces deficits and mounting debt.