With members of Congress no closer to reaching a deal to avert automatic spending cuts next year, the House Administration Committee warned lawmakers on Thursday to get ready.

The Office of Management and Budget predicts that the legislative branch will lose 8.2 percent of its fiscal 2013 allocation if sequestration, part of last year’s debt limit deal, comes to pass at the start of the new year.

But in a “Dear Colleague” letter sent Thursday, outgoing House Administration Chairman Dan Lungren, R-Calif., said the cuts to House leadership, committee and member offices could be much higher.

“By the time a sequester could be triggered, three months of [fiscal year] 2013 will have already passed, during which time spending continued at previously appropriated (i.e., higher) levels,” Lungren wrote. “As a result, the effective rate of cuts to each covered amount for the remaining nine months of [fiscal year] 2013 could reach 11 percent.”

On top of the 11.4 percent decrease House office budgets have experienced in the 112th Congress, sequestration could mean lawmakers will absorb 22.4 percent in reductions by the end of 2013 — the steepest cuts in memory to the coffers that fund everything from staff salaries to constituent communications.

“Members and committee chairs should be prepared to operate under these reduced budget levels for the duration of any sequester, beginning on Jan. 3, 2013,” Lungren continued. “Members and committee chairs are further advised that because we are already in [fiscal year] 2013, and the amount available for this fiscal year is fixed by law, attempts to ease the impacts of a possible sequester by making pre-payments this calendar year will not increase the amount of money made available to any office making pre-payments.”

The House Administration Committee has included additional guidance for member offices on its website to help them prepare for the effects of the automatic cuts. It notes that because congressional staffers are not subject to “statutorily structured pay rates,” their salaries are not protected from sequestration and lawmakers can choose to help offset budget cuts by freezing or reducing paychecks — something many offices have already started doing over the last two years. Congressional offices can also furlough employees.

There are many unknowns at this point: how many offices would have to fire employees, what the effect of sequestration would look like on the Hill — from Capitol Police presence to Architect of the Capitol maintenance projects — and whether employees would lose benefits.

”Although government contribution accounts are not exempt from sequestration, the exact impact to benefits is unclear at this time,” according to the guidance. “The committee will notify members and staff prior to the implementation of any changes.”