Cricket: Steve Smith didn't hide his frustration at being given out caught behind to the bowling of Marcus Stoinis in a questionable decision after reaching his century.

Cricket superstar Steve Smith has pleaded guilty to a Level 1 Code of Conduct breach during a Sheffield Shield match in Sydney.

Smith was fined 25 per cent of his match fee after showing dissent at an umpire’s decision during a match between NSW and Western Australian at the Sydney Cricket Ground.

After passing a century on Tuesday morning, the 30-year-old batsman attempted to loft a Marcus Stoinis delivery to third man. The wicketkeeper gloved the ball and the umpire raised his finger after a half-hearted appeal.

On 103 at the time, Smith was visibly unhappy with the umpire’s decision, dropping his arms and shaking his head, clearly believing he didn’t hit it.

Slowly making his way off the ground, the former Australian captain regularly looked back at the umpires, even demonstrating to teammate Trent Copeland that he’d missed the ball.

“I got given out, didn’t I. You are allowed to be disappointed at times,” Smith said.

“I didn’t feel as though I hit it, but that happens and you’ve just got to move on.”

Match referee Peter Marshall fined Smith 25 per cent of his match fee on Thursday morning for the incident.

Steve Smith guilty of dissent after his 1st innings dismissal in SCG Shield game pic.twitter.com/gHqqlMRNRE — Daniel Brettig (@danbrettig) November 14, 2019

Smith is the seventh player to be charged under the Cricket Australia Code of Conduct this summer. Fellow international stars Marcus Harris and Glenn Maxwell have also been sanctioned for similar offences.

Smith’s century on Tuesday was the 42nd and slowest of his first class career, lasting for more than five hours as he soaked up 295 deliveries. The classy innings helped NSW to a formidable first innings total of 8/444 declared.

Smith claimed a bizzare wicket during day four of the Shield match, Josh Inglish’s full-blooded cover drive ricocheting off a fielder’s leg, only to be caught by Nick Larkin on the other side of the pitch.

NSW is top of the Sheffield Shield ladder after it secured a comprehensive 224-rin victory against Western Australia.

The Blues may not see much more of Smith this summer as he embarks on international duty, which includes Test series against Pakistan and New Zealand.

The first Test against Pakistan starts next Thursday in Brisbane.