New Democrat MPs want to take the battle over their allegedly improper use of parliamentary resources all the way to the Supreme Court of Canada.

Their lawyer, Julius Grey, wrote Justice Minister Peter MacKay on Friday, asking him to refer the matter to the top court.

The NDP wants the court to advise whether the rulings of the secretive, multi-party board of internal economy are subject to judicial review.

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The board, which polices House of Commons spending, has ruled that 68 current and former NDP MPs improperly pooled their Commons office budgets to pay the salaries of 28 staffers working in satellite party offices in Montreal, Quebec City and Toronto.

The board sent bills earlier this month to each of the MPs demanding that they personally repay a total of $2.75 million. It gave the MPs 90 days to make the reimbursements.

In a separate letter Friday to the acting Commons clerk, Grey advised that the money will not be repaid until there is a "final judgment" on the matter.

However, if MPs do not voluntarily repay, the board has warned it will recoup the money by garnisheeing their salaries or other sources of Commons funding.

The NDP applied last fall to the Federal Court to overturn the board's ruling on the satellite offices and a previous ruling ordering MPs to repay just over $1 million in parliamentary mailing privileges used to paper ridings across the country with partisan missives.

However, the court challenge was suspended last November after the NDP initiated negotiations on an out-of-court settlement.

While New Democrats have furiously denounced the board as a partisan "kangaroo court" and have predicted they'll be vindicated by a "real court," their federal court application has not been reactivated, until now.

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Grey filed a new application Friday, asking the court to set aside the board's decision to bill MPs for their share of cost of the satellite office scheme. He called the ruling "unreasonable, arbitrary and incorrect" and the product of "political bias."

Whether the court will even agree to hear the matter is doubtful. Courts have been reluctant in the past to interfere with Parliament's exclusive right to administer its own affairs.

MacKay's office declined to say whether he'll agree to seek the Supreme Court's advice on that question. His office referred media queries to government whip John Duncan, who is a member of the board of internal economy.

For his part, Duncan said the request to refer the matter to the Supreme Court is a "stunt" that suggests the NDP knows its Federal Court challenge will never get off the ground.

"This move shows the NDP will do anything to avoid paying back what they owe for misuse of parliamentary resources," he said in an email statement.

"Now it appears they no longer even have confidence in their own attempt to stall by using the Federal Court. The NDP should show some respect for the taxpayers of Canada and immediately pay back every dollar they improperly spent."