These terms describe different events
Prorogation formally ends a parliamentary session, while dissolution ends the House of Representatives for an election. The Senate is a continuing chamber, although Senate elections occur periodically and a double dissolution can dissolve both houses under special constitutional conditions.
Political reporting sometimes uses these terms loosely, but they have different constitutional consequences.
Dissolution and the election period
When the House is dissolved, members cease to sit as a House and the election process proceeds under the writ timetable. Government continues in office during the election period, subject to caretaker conventions that guide major decisions and appointments.
Parliamentary committees and unfinished business can be affected by dissolution, which is why the timing of bills near an election can matter.
Prorogation
Prorogation brings a session of Parliament to an end without necessarily triggering an election. Historically it has been used less frequently in modern federal practice than ordinary adjournments, but it remains part of the constitutional framework.
Its procedural effect can include ending certain parliamentary business, although the treatment of matters depends on parliamentary rules and subsequent action.
The opening of a new Parliament
After an election, a new Parliament is summoned and formally opened. Members and senators take or affirm the required oath, presiding officers are chosen where necessary and the Governor-General delivers the opening speech outlining the government's program.
The speech is politically significant but is not itself legislation. Bills must still be introduced and passed through the ordinary parliamentary process.
Why this matters for legislative timing
A bill that has not completed its passage before an election may lapse and need to be reintroduced in the new Parliament, depending on the chamber and procedural rules. Committee inquiries can also be affected by the end of a Parliament.
When a government says legislation will pass 'before the election', the parliamentary calendar, sitting days and chamber numbers can therefore be just as important as the policy announcement.
Primary sources and further reading
We use authoritative Australian institutions as the starting point for this explainer. Follow these links for the underlying rules, official guidance and current details.