The former Premier and State Liberal Party Leader was set to retire before the 2010 election, with local police officer Terry Boylan, for the Liberal Party and postal officer John Rohde, from Labor, seeking to take the seat.

Mr Kerin said the “wear and tear” had led to his decision and he thought it was time to move on so Frome can have “a bit of new energy”.

“It has been a great experience and my constituency has been fantastic,” he said.

Mr Kerin says he led a busy 15 years in politics and he will try to keep an involvement in the local area.

A by-election will be held to fill the vacant seat with Mr Kerin naming December 13 as his preferred date.

Mr Kerin became the Member for Frome in 1993 when the electorate was re-established after being abolished in 1977.

He later became Deputy Leader of the party in 1998.

When Premier John Olsen resigned in 2001, Mr Kerin took over the position, losing to Mike Rann in 2002.