It turns out for much of his time in office, Scott Morrison was more than just Prime Minister.

He took on the powers of five additional portfolios, and did so almost entirely in secret.

So what were these extra roles, and why did he take them on?

Health

The first — and arguably the least-controversial — was duplicating the role of the then-health minister.

On March 14, 2020 — when the uncertainty around COVID-19 was near its peak — Mr Morrison made himself, effectively, a secondary health minister.

The reasoning he gave in a press conference on Wednesday was that the health minister carried incredible special emergency powers under the Biosecurity Act, and some of it was being put to use.

Finance

On March 30, 2020, Mr Morrison also took on the powers of the finance minister, who at the time was Mathias Cormann.

At his press conference, Mr Morrison argued there were "massive financial delegations" available only to the finance minister and — like the health minister — precautions needed to be taken.

The finance minister is different to the treasurer. The former is responsible for the machinery of government, how all the various public service functions work.

It's a big, important and influential role.

Treasury and home affairs

More than a year later, two more significant appointments were made. 

In May, 2021, Mr Morrison took on both the treasury and home affairs portfolios.

Neither minister — Josh Frydenberg nor Karen Andrews — were told, and both have expressed shock and disappointment.

Their portfolios are some of the most senior in government. 

The treasurer is responsible for the federal budget, which was delivered only days after the change was made.

That budget outlines how federal government money is spent.

Industry, Science and Resources

The really odd one out among the bunch of ministries that Mr Morrison appointed himself to is the mega-portfolio of industry, science and resources.

Shortly before taking on home affairs and treasury, Scott Morrison made the call to take on oversight of the diverse department.

The reason, Mr Morrison has made clear, was entirely separate to the pandemic.