Issue of writs
Writs for the election of senators are issued by the state governor under the authority of the relevant state legislation. The practice is for the governors of the states (when the elections are concurrent) to fix times and polling places identical with those for the elections for the House of Representatives, the writs for which are issued by the Governor-General.
In practice, the Prime Minister informs the Governor-General of the requirements of section 12 of the Constitution, which provides that writs for the election of senators are issued by the state governors, observes that it would be desirable that the states should adopt the polling date proposed by the Commonwealth, and requests the Governor-General to invite the state governors to adopt a suggested date. Theoretically, a state could fix some date for the Senate poll other than that suggested by the Commonwealth, provided it is a Saturday. Different states, too, could fix different Saturdays for a Senate poll.
This power vested in the states to issue writs for Senate elections, fixing the date of polling, gives expression to the state basis of representation in the Senate.
The Constitution provides that, in the case of a dissolution of the Senate, writs are issued within ten days from the proclamation of the dissolution.
The Governor-General issues the writs for elections of territory senators.