In Australia, the 151 members of the House of Representatives equates to 1 MP for approximately every 134,000 people of voting age (or as a ratio 1:134,000)*. While there is no ‘optimal’ size of a parliament (given physical space and budgetary constraints), some commentators have highlighted the inherent representational implications involved. Accordingly, this Flagpost article considers the historical context, assesses the potential impacts of changing the size of the parliament, and statistically situates the Australian parliament among international comparisons.

Learning from history

Debate around Australia’s parliamentary representation pre-dates Federation, as section 24 of the 1891 draft Commonwealth of Australia Bill attests. The wording was subsequently changed in the 1900 Commonwealth of Australia Constitution Act (also section 24) from ‘each state shall have one Representative for every thirty thousand of its people’ to become ‘the number of such members [of the House of Representatives] shall be, as near as practicable, twice the number of the senators’. This is more commonly known as the nexus-provision, and remains an important consideration when contemplating expanding the parliament.

Since Federation the size of the House of Representatives has undergone two major expansions. In the 1949 federation election it changed from 75 seats to 123 seats, and to 148 seats in the 1984 election (a 1:74,777 ratio). Four years later Australia’s parliament moved to its current site on Capital Hill, designed with chamber seating for 172 MPs and provision for up to 240.

Canvassing the options

Within submissions to an ongoing Joint Standing Committee on Electoral Matters (JSCEM) inquiry into the 2022 federal election, multiple commentators have offered potential expansion scenarios. For example, psephologists Malcolm Mackerras (p. 13) and Kevin Bonham (pp. 9–11) have advocated an increase to 175 MPs, with the latter also positing a potential level of 200 MPs. In terms of representation ratios, 175 MPs would equate to 1:115,737, while 200 MPs would be 1:101,270.

Alternatively, the Australia Institute advocates for the largest expansion – 50% more parliamentarians across both chambers (p. 3). Factoring in the Constitution’s nexus provision, this would incorporate 227 MPs (a 1:89,225 ratio).

What are the implications?

The Australia Institute justifies its proposal (pp. 42–8) by claiming that a 50% increase would:

• Increase representation in Australia’s two territories (ACT/NT)
• Provide for ‘one vote, one value’, where each electorate has the same number of voters
• Increase the number of available candidates for ministerial positions
• Reduce the geographic size of non-metropolitan electorates

Territory representation is an increasingly topical issue, given the ACT’s population incrementally catching up to Tasmania, and the Government’s 2020 legislation which maintained the Northern Territory’s 2 House of Representatives seats. The ‘one vote, one value’ principle is also incorporated in the JSCEM’s current parliamentary inquiry terms of reference.

In terms of potential costs, any increase to the size of parliament would not be cheap, including the salaries, expenses and allowances of the additional parliamentarians as well as their staff. It is likely there would also be the need for additional flow-on resources for the parliamentary departments. Accordingly, any future changes would need to weigh up the budgetary and administrative considerations with the public benefit enabled by greater access to national parliamentary representatives, argued for by advocates.

Comparing apples with apples

For perspective, it is worth looking internationally at the size of comparable parliaments. The Inter-Parliamentary Union’s Parline database identifies 178 national parliaments incorporating direct election of representatives. Of these, 75 (42%) have two parliamentary chambers, including Australia. Factoring in all 75 nations, the average representation ratio is 1 MP for every 112,636 people of voting age. However, population size skews this substantially, ranging from India’s vast 969,400,000 voting age population (a 1:1,785,267 ratio) to Palau’s mere 14,000 (a 1:875 ratio). Notably however, Australia’s 1:134,132 ratio (based on a voting-age population of 20,254,000) ranks 13th highest among the 75 nations.

It is also instructive to compare Australia with other specific Westminster-system parliaments and the United States. Within this, Canada has an MP to voting age population ratio of 1:91,538 and the United Kingdom has 1:81,771, while New Zealand’s much smaller population creates a ratio at 1:33,083. Conversely the United States’ substantially larger population provides a ratio of 1:602,903.

In terms of investigating similar voting-age populations, there are 10 countries closer aligned (+/-30%) with Australia. Of these, Australia has the second highest ratio of voting-age population to MPs, behind only Uzbekistan (1:148,487). Additionally, Australia’s representation ratio (1:134,132) is more than 44% higher than the 10-nation average (1:92,836).

Representation of directly elected members by voting-age population

Accordingly, when compared to other parliaments, Australian voters are relatively unrepresented in terms of the number of parliamentarians.

For further reading on how any changes could be implemented, see the Parliamentary Library Quick Guide The process for, and consequences of, changing the size of the Commonwealth Parliament.

*all cited population statistics are current up to 2021 and derived from the United Nations Department of Economic and Social Affairs, Population Division (2022) [Population by age and sex – broad age groups]. World Population Prospects 2022, Online Edition.