That sum will be on top of the $1.17 million in free mailing privileges the board ruled in June were wrongly used by NDP MPs to send almost two million mass partisan mailings to households in 26 ridings.
John Duncan, a Conservative MP and spokesman for the multi-party committee, says the latest dollar figure has yet to be determined, but he expects it to be a "significant number" since the wrongdoing dates back to 2011.
"The rules are clear and it is clear, once again, that the NDP has broken the rules," Duncan told a news conference on Parliament Hill.
The NDP used parliamentary resources to pay for offices that were not properly authorized, he said, adding Commons administrators are being asked to prepare various options to ensure the recovery of the funds.
New Democrats have already launched a court challenge against the board's ruling on the mailings, and are expected to do the same on the satellite office issue.
NDP whip Nycole Turmel said earlier today that her colleagues have done nothing wrong.
Turmel blames Conservatives and Liberals on the board of internal economy for indulging in a partisan witch hunt against the NDP.