The NDP is expected to face a blistering new report from House of Commons administration on Monday into its use of satellite offices outside of Ottawa, CBC News has learned.

Sources tell CBC that Commons administration officials will present an independent analysis of NDP satellite office expenses and billings to the secretive all-party Board of Internal Economy.

The NDP is already facing the repayment of untold thousands of dollars over improper mailings.

On Monday, the House Administration is also expected to weigh in on that, presenting the value of the mailing the NDP used and options for repayments. The NDP might be forced to pay back thousands of dollars in mailing costs.

The House Administration analysis of the NDP satellite offices examined where several House of Commons employees actually performed their function. NDP Leader Tom Mulcair has insisted there is nothing wrong with doing House of Commons work from a remote location.

The House Administration will also decide if parliamentary funds were improperly used for party work. One source said the report will be damaging to the NDP.

The question remains how members of the board will respond to the report. A source has said if it is damning, one option is to ask legal authorities to investigate the findings.

The NDP ran offices in cities including Montreal and Toronto with staff paid with parliamentary funds, but the party has always maintained it complied with Commons rules. Mulcair has said his party informed the House of Commons administration staff about the nature of staffing at the offices.

Join host Evan Solomon for CBC Radio's The House, Saturday at 9 a.m. on CBC Radio One and SiriusXM channel 169

"I'm not David Copperfield," Mulcair said at the committee on procedure and House affairs. "I can't make an office disappear. It was open. It was transparent. It was public."

Mulcair also told the committee that the Board of Internal Economy changed the rules in April to prevent staff from working outside of Ottawa. The NDP subsequently complied with the new rules.

However that testimony has been contradicted by a memo House Clerk Audrey O’Brien sent to the Board of Internal Economy. The memo says the House was not informed about NDP staff working outside of Ottawa. The Speaker of the House, Andrew Scheer, has also maintained his office was not informed of the way the satellite offices were staffed.

The report on the satellite offices follows on an earlier board ruling that found the NDP broke House rules by using parliamentary resources for mailings sent out to various ridings across the country.

The NDP has also fought back against that ruling, dismissing the ruling of the board as a “kangaroo” court run by their political opponents. The party maintains it has consulted with the House of Commons prior to any mailings and abided by all the rules.

To buttress its argument, the NDP has pointed to an April 2013 letter sent to Scheer's office by party whip Nycole Turmel that asked for a ruling on the mailings issue.

"We conducted extensive consultations with the House of Commons and the Speaker to confirm that this program respected all applicable rules," the NDP said.

However, Scheer has contradicted the NDP, saying his office was not consulted on the mailings issue.

Scheer's office later had to clarify that his answer referred to the Bourassa mailout and acknowledged the letter NDP staff emailed to reporters after the meeting. Scheer noted in his written response that the letter from NDP whip Nycole Turmel asked about a range of issues regarding House mailing privilege.

The Board of Internal Economy meets on Monday.

Join host Evan Solomon for CBC Radio's The House, Saturday at 9 a.m. on CBC Radio One and SiriusXM channel 169