A familiar black-robed figure will be missing from the table in front of the Speaker's chair when the House of Commons reopens for business later this month.   

House of Commons Clerk Audrey O'Brien will be on extended medical leave while she recovers from emergency surgery.

Her absence was announced in a memo sent out by Speaker Andrew Scheer on Thursday.  

"At her request, and in consultation with the House Leaders of all parties, I have asked the Deputy Clerk, Mr. Marc Bosc, to assume the role of Acting Clerk on an interim basis during Ms. O’Brien’s absence," he noted.

"I know you will join me in wishing Ms. O’Brien well in her recovery."

O'Brien had been on temporary medical leave from May 26 to late July for an earlier planned surgery, during which time Bosc also stepped in.

"Timing is never ideal for this type of event, but I have been on a waiting list for surgery for two years and have finally been scheduled," she said in a note sent to colleagues before she left.

"I am fortunate to be able to leave the House in your capable hands, under Marc's leadership," she added. "Bon courage during the final sitting weeks before the summer."

The statement from the House did not include disclose details on her latest medical issue.

O'Brien 'outstanding public officer': NDP

Speaking on behalf of the New Democratic Party caucus, Greta Levy called the news "upsetting." 

"Audrey O'Brien is an outstanding public officer who's earned the respect of everyone in the House," she noted. 

"We certainly look forward to welcoming her back as soon as she is able."

Both the Conservatives and the Liberals expressed similar sentiments.

"We wish Mrs. O'Brien a speedy recovery and look forward to her return," PMO spokesman Stephen Lecce told CBC News.

"The Liberal Party is sending our thoughts to Ms. O'Brien, and wish her a speedy recovery," said Liberal spokeswoman Kate Purchase.

O'Brien was appointed to the top Chamber job in 2005, and is the first female to hold the position. 

As the senior House officer, she advises the Speaker and all MPs on parliamentary procedure, precedent and practices.  She began her career on the Hill as a committee clerk in 1976.

The official biography on the parliamentary website states that "in (O'Brien's) 25 years of service to the institution, she has served seven Speakers and members of nine Parliaments."

She is also the co-editor of the current version of  House of Commons Procedure and Practice, which she produced in cooperation with her acting replacement, Bosc, as well as other House staff.