"What would happen if the coalition of parties in government decided to break their coalition?"

After a federal election, the party or coalition of parties with the support of the majority of members elected to the House of Representatives becomes the Australian Government.

To remain in office the government must keep the support of the majority of members in the House.

If a government coalition decided they no longer wanted to work together—and this resulted in the government no longer having the support of the majority of members of the House—several things could happen;

Although government is formed in the House of Representatives, there are also members of the government in the Senate. The government may or may not hold the majority of seats in the Senate.

diagram to help explain What would happen if the coalition of parties in government decided to break their coalition?