A disclaimer noting that ministers may be sworn to administer other portfolios without it being shown on the official parliamentary list was added just days after Scott Morrison took over as prime minister in 2018.

AAP initially reported last week the disclaimer change was made after the 2019 election.

But a further check of the parliamentary records showed the first use of the disclaimer was on a document dated August 28, 2018, four days after Mr Morrison was sworn in to take over from Malcolm Turnbull.

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.

Prior to Mr Morrison taking over as prime minister, the ministry list 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.”

However, the August 28 document showing his first ministry added the 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.

Mr Morrison’s office has been sought for comment.

A former cabinet minister told AAP it was possible the disclaimer was added to cover instances where ministers stood in for other ministers when they were away.

But the source said this should not detract from the importance of a person exercising the power of a minister to be publicly declared as such.

The disclaimer is still used by the Labor government.

Prime Minister Anthony Albanese is due on Monday to receive advice from the solicitor-general on whether there were any legal implications of Mr Morrison’s actions.

He has also flagged possible improvements to make decision-making more transparent.

The Greens have asked Speaker Milton Dick to consider a referral of Mr Morrison to the privileges committee to consider whether he misled parliament.

Mr Morrison told reporters last week he had taken on the extra 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 whose portfolios he had taken without telling them.

Mr Morrison used a simple legal instrument signed by the governor-general to take on health on March 14, 2020; finance on March 30, 2020; industry, science, energy and resources on April 15, 2021; and treasury and home affairs on May 6, 2021.

– AAP