Former prime minister Scott Morrison informed parliament after the 2019 election that ministers may be sworn to administer other portfolios without it being noted on the official list.
Mr Morrison is facing questions over his secret swearing-in to five portfolios - finance, treasury, health, home affairs and resources - between March 2020 and May 2021.
Like other former prime ministers before him, he routinely tabled in parliament revised lists of ministers when changes were made to the frontbench.
The list tabling is usually done at the start of question time in the House of Representatives and the full list is routinely published in the official Hansard record.
Mr Morrison's first ministry list after becoming prime minister in 2018 came with a disclaimer: "As a general rule, there is one department in each portfolio. However, there is a Department of Human Services in the Social Services portfolio and a Department of Veterans' Affairs in the Defence portfolio. The title of a department does not necessarily reflect the title of a minister in all cases."
Ministry lists from then until the final sitting day before the May 2019 election were tabled with the same disclaimer.
However, at the July 2 parliamentary sitting - the first after the coalition's election win - the following sentence was added to the ministry list disclaimer: "Ministers are sworn to administer the portfolio in which they are listed under the 'Minister' column and may also be sworn to administer other portfolios in which they are not listed."
It is unclear which ministers held "other portfolios in which they are not listed" since the time of the disclaimer, beyond the five disclosed by the former prime minister.
Comment was being sought from Mr Morrison's office on why the disclaimer was added.
Governor-General David Hurley said in a statement on Wednesday he had "no reason to believe that (ministerial) appointments would not be communicated" once changes were made to portfolios.
The Greens have asked Speaker Milton Dick to consider a referral of Mr Morrison to the privileges committee to consider whether he misled parliament.
Former minister Karen Andrews has called for him to quit parliament.
Mr Morrison told reporters on Wednesday he had taken on the portfolios because he considered emergency powers were needed to deal with COVID-19, which was declared a global pandemic in March 2020.
But he said he had only used the powers once - in the case of overriding the resources minister in relation to a NSW gas exploration permit.
He has since apologised to the ministers involved.
