Parliament of Australia
From 1901 to 1949, the House consisted of either 74 or 75 members (the Senate had 36). Between 1949 and 1984, it had between 121 and 127 members (the Senate had 60 until 1975, when it increased to 64). In 1977, the High Court ordered that the size of the House be reduced from 127 to 124 members to comply with the nexus provision. In 1984, both the Senate and the House were enlarged; since then the House has had between 148 and 150 members (the Senate has 76).
Australian Senate
Under Section 24 of the Constitution, the number of members of the House of Representatives has to be "as nearly as practicable" double the number of Senators. The reasons for the nexus are twofold. These are a desire to maintain a constant influence for the smaller states and maintain a constant balance of the two Houses in case of a joint sitting after a double dissolution. A referendum held in 1967 to eliminate the nexus failed to pass.