Mr McKim was chosen by party members to replace outgoing Greens Senator Christine Milne, but the appointment still must be ratified by the State Parliament.

Under the Constitution, the replacement for a casual vacancy must be of the same party as the departing senator, but the State Parliament can decide to leave the position vacant until the following election.

Mr Gray said the Senate had become the plaything of major parties and needed urgent reform.

‘‘The federal government has been forced into the position where the country is almost ungovernable and that is largely due to the Senate,’’ he told The Examiner.

‘‘They’ve distorted the whole thing so it’s no longer a state’s house, as intended at Federation, and it’s now a party political house.’’

Mr Gray said the Parliament should at least debate Mr McKim’s promotion, rather than just rubber stamp the deal.

‘‘This business of parties just nominating someone who happens to be their favourite son or daughter at the moment isn’t what the Constitution intended,’’ he said.

‘‘They should use this opportunity for a full debate about the importance of the Senate to Tasmania and about the reforms that need to take place for a fair deal for Tasmania.’’

Mr Gray said he would like to see the Senate move to a single-member electorate model, with 12 divisions in each state, similar to the Tasmanian Legislative Council.

A spokeswoman for Premier Will Hodgman said the government had ‘‘no intention to depart from established practice’’.

In 1987, during Mr Gray’s government, the Parliament blocked the appointment of Labor’s John Devereux.

The matter was not resolved as a double dissolution was called soon afterwards and Mr Devereux was elected to the Senate.