Just before losing the leadership, then-prime minister Tony Abbott and his chief of staff, Peta Credlin, were planning to extend the ministerial wing in Parliament with two large extensions in order to accommodate the increasing number of staffers working for the government in the building.

When Malcolm Turnbull took the leadership, the plans were quietly killed off.

Since then, Labor has been chasing bureaucrats in Senate estimates hearings to find out exactly what happened. In particular, Labor’s leader in the Senate, Penny Wong, has been seeking access to a letter Abbott sent to the Speaker of the House of Representatives and the President of the Senate about the proposed extension. In a response to a question on notice this week, Senate President Stephen Parry indicated that Speaker Tony Smith was blocking the release of the letters.

“The Speaker has confirmed that he does not agree to the letter being provided to the Committee. Accordingly, I am unable to provide a copy of the letter to the Committee,” Parry said.

Labor asked why one chamber could ask for the letter and be blocked by the other chamber, and Parry said he was just following established practice. “If one Presiding Officer does not agree, then the other cannot unilaterally choose to release such correspondence.”