Cricket-Smith rules out challenge to ball-tampering ban

* Smith accepts ban, says CA wanted to send strong message

* Players have until Thursday to contest sanctions (Adds reactions, details)

MELBOURNE, April 4 (Reuters) - Banned former captain Steve Smith will not contest the sanctions imposed on him by Cricket Australia (CA) for his role in last month's ball-tampering scandal in South Africa, the batsman said on Wednesday.

Smith and former vice captain David Warner were handed 12-month bans, while batsman Cameron Bancroft was suspended for nine months after the latter was caught using a piece of sandpaper on the ball in the third test in Cape Town.

"I would give anything to have this behind me and be back representing my country," Smith said on his verified Twitter account. "But I meant what I said about taking full responsibility as Captain of the team.

"I won't be challenging the sanctions. They've been imposed by CA to send a strong message and I have accepted them."

Smith and Warner were also stripped of their leadership positions for their role in the March 24 incident and are set to lose substantial earnings after sponsors dropped them, with the bans meaning they will miss this year's Indian Premier League.

Smith and Bancroft were also barred from holding leadership positions within the Australian team for two years, while Warner will never be able to hold such a position again.

The trio returned to Australia at the end of last week, where all three gave emotional news conferences in which they accepted full responsibility for their actions.

Despite the backlash to the incident, Australian Cricketers' Association (ACA) has called for a reduction in the bans meted out to the players, describing them as "disproportionate".

"As I stated yesterday, the players have our support whatever they decide," its president Greg Dyer said in an ACA tweet on Wednesday.

"This is a deeply personal decision with unique circumstances and complexities for each person.

"We continue to support the three men at this difficult time."

The players have until Thursday to appeal their bans with Smith the first to confirm he will not contest the sanctions.

The scandal also prompted Australia coach Darren Lehmann, who was cleared of any wrongdoing by the CA, to step down after the final test against South Africa.

The ball-tampering controversy was the low point of an already tempestuous tour in which the sides split the opening two tests before South Africa went on the register easy victories in the remaining two matches to win the series 3-1.

(Reporting by Sudipto Ganguly in Mumbai; Editing by John O'Brien/Amlan Chakraborty)