Western Australia 460 for 9 dec (Cartwright 153, Goodwin 94, Agar 74, Fanning 68, Kuhnemann 5-100) beat Tasmania 317 (Owen 83, Jewell 61, Paris 4-45) and 98 (Agar 3-12, Couch 3-15) by an innings and 45 runs

A week after George Bailey issued a call for Australia's left-arm spinners to stand up, Western Australia's Ashton Agar virtually said, "Don't forget about me".

WA extended their lead at the top of the Sheffield Shield ladder with a comprehensive thrashing of Tasmania in Hobart, with left-armer Agar claiming 3 for 12 in 17.5 testing overs in the second innings.

The visitors dismissed Tasmania for 98 to win by an innings and 45 runs, with paceman Brody Couch becoming the first bowler to take a Sheffield Shield hat-trick for Western Australia in their history.

Couch had Jake Doran lbw, before Lawrence Neil-Smith chopped a ball onto his stumps and Couch clean bowled Sam Elliott. The three wickets came in the first over after tea, killing off any hopes of Tasmania hanging on for a draw after they started the final session at 89 for 6.

Agar's strong performance came after New Zealand left-arm spinners Mitchell Santner and Ajaz Patel played crucial roles in a historic 3-0 Test series win in India.

Just last week Australian chairman of selectors Bailey said left-arm orthodox spin was "an incredible skillset in the subcontinent", with a series in Sri Lanka next year on the horizon.

"Realistically there's not a huge amount of players in domestic cricket that are doing it, so it is something we are looking to expose," Bailey said.

Agar showcased great variety on the final day and dried up the runs, allowing the pace attack at the other end to also shine.

WA, winners of the past three Shield titles, had earlier taken a 143-run first innings lead The hosts resumed at 10 for 2 needing one of their top order to dig in for a big score.

It was not to be, as left-arm quick Joel Paris swung a pearler in to Charlie Wakim to trap him lbw without troubling the scorers to the fifth ball of the morning.

Nightwatchman Gabe Bell was undone by a perfect left-arm orthodox delivery from Agar that curled in and spun away to hit the top of the off stump. Captain Jordan Silk was unable to get going and was trapped in front by an Agar skidder.

Paris, 31, showcased why he is one of the leading exponents of left-arm pace bowling in the country. His 2 for 18 in the second innings complemented the 4 for 45 he claimed in the first. At times he was unplayable on a surface that offered very little.

The WA performance was more meritorious considering strike bowler Matthew Kelly was rubbed out after suffering a hamstring injury in the first innings.