Incumbent MP David Koch, author Simon Illingworth, former Victorian Farmers Federation president Simon Ramsay, Colac businessman Richard Riordan and Daylesford real estate agent Paul Johnson have all thrown their hat into the

ring for Western Victoria region preselection.

Candidate interest in the position has been sparked by long-serving MP John Vogels' decision to retire at the next election.

Under a Coalition agreement, the Liberal Party occupies the first two places on the five-name Legislative Council ballot with the National Party taking third spot.

The preselection for the two Liberal places and the Nationals spot will be decided in November at separate party conventions.

The Nationals are yet to finalise the state upper house preselection process.

Meanwhile, in federal politics, the Nationals have deferred a decision to stand a candidate in Wannon until next month. At a convention in Hamilton last Sunday the Liberal Party chose former diplomat Daniel Tehan to replace David Hawker as

its Wannon candidate.

Nationals state director Luke O'Sullivan said the fact Mr Tehan came from outside the electorate was a major consideration in standing its own candidate in Wannon.

``We will consult more widely in the next month with Wannon party members to consider whether it would be worth standing a candidate in Wannon and, for that matter, names of those interested in standing,'' Mr O'Sullivan said.

Former federal election candidates for the Australian Greens, Lisa Owen and Gillian Blair, said they both would consider contesting Wannon preselection for their party.