In practical terms, what were the responsibilities of past parliamentarians who were appointed as a 'Minister without Portfolio'?

The role of ministers and shadow ministers: make or scrutinise decisions, specialise in key areas, debate and vote on bills.

Role of frontbenchers in the Australian Parliament.

Parliamentary Education Office (peo.gov.au)

Role of frontbenchers in the Australian Parliament.

The role of ministers and shadow ministers: make or scrutinise decisions, specialise in key areas, debate and vote on bills.

Parliamentary Education Office (peo.gov.au)

Description

This graphic shows that ministers and shadow ministers are also known as 'frontbenchers' because they sit on the front bench of the chamber. Their roles include: making and scrutinising key decisions; specialising in key areas of governance; and debating and voting on bills.

Ministers are members of the Australian Government who have been allocated an area of responsibility for how Australia is run. This area of responsibility is known as a portfolio and some examples include health, finance, defence, and immigration. Ministers are responsible for developing government policy and putting government decisions into action.

In the past members of the government have been appointed as a minister without a specific portfolio. Examples include Stanley Bruce in 1932, Enid Lyons in 1949 and James Killen in 1982.  

In the case of Stanley Bruce, Prime Minister Joseph Lyons appointed him to the role so he could represent the Prime Minister and Australian Government in London, without the limitations of a specific portfolio.

In the examples of Enid Lyons and James Killen, they were both given the responsibility of Vice-President of the Federal Executive Council. This is not a specific government portfolio but a role usually performed by a senior government minister who is part of Cabinet.