'Excessively disappointed': Steve Smith laughs off Sheffield Shield dissent charge

Former Australian captain Steve Smith has laughed off his punishment for dissent in the Sheffield Shield and defended his reaction.

Smith was fined a quarter of his Shield match fee for showing dissent after being given out on Tuesday on day two of New South Wales' match against Western Australia.

Smith momentarily remained at the crease and shook his head after he was deemed to have nicked a Marcus Stoinis delivery to wicketkeeper Josh Inglis standing up at the stumps.

The Test star had reached his second century of the Shield season an over earlier but the dismissal ended a marathon 335-minute knock at 103.

Smith said after the day's play, "I didn't think I hit it. You're allowed to be disappointed."

At the press conference on Friday announcing that Smith would be playing in the Big Bash League with the Sydney Sixers, he joked about the dissent charge.

"Excessive disappointment it was, I think. I was excessively disappointed," he laughed when asked if he thought it was unfair punishment.

"I got out at 100 after blocking them for such a long time. I faced 300 balls and it was about time to start getting on with the game and slogging a few. I was excessively disappointed not to do that.

"Those things can happen. I didn't think there was a heap in it but it is what it is, I'll cop it and move on."

Though it was hardly a huge controversy, as his on-field first indiscretion since the infamous ball tampering saga, Smith admitted toning down his dismissal reactions might be an area of his game that he needs to clean up.

"I get pretty disappointed every time I get out. Perhaps it is something I need to work on.," Smith said.

"I've got so many different mannerisms that I do that I don't know that I'm doing. So perhaps it is something that I need to look at when I get out."

Smith is set to make his first Test appearance on home soil for nearly two years next week in Brisbane following his much-publicised 12-month ban from cricket.

- with AAP