THERE will be a loser and a winner in tonight's Liberal leadership spill and betting on who will walk away with the title of Prime Minister has already begun.

Online bookmaker sportsbet.com.au has opened a market on the impending ballot.

Malcolm Turnbull is expected to win the ballot, priced $1.10, with Prime Minister Tony Abbott at $6.00.

The announcement of a leadership challenge has caused a bounce for the Liberals in Canning, with Liberal candidate Andrew Hastie shortening from $1.27 into $1.20 following today's announcement while Labor's Matt Keogh has drifted back out to $4.00.

Malcolm Turnbull's decision to challenge Abbott for the Liberal leadership has seen the Coalition shorten from $1.73 into $1.50 to win the next Federal Election, while Labor has gone from $2.15 out to $2.65.

Liberal leadership ballot

$1.10   Malcolm Turnbull

$6.00   Tony Abbott

Canning By-Election

$1.20   Liberal (Andrew Hastie)

$4.00   Labor   (Matt Keogh)

Others quoted

Next sworn-in government

$1.50   Coalition

$2.65   Labor