South Australian captain Johan Botha has admitted to ball tampering but will appeal a one-match ban that rules him out of the state’s most important match in 18 years.

Cricket Australia on Friday suspended Botha for next week’s last-round Sheffield Shield match against Tasmania, which will determine whether the Redbacks reach the final for the first time since their 1995-96 win.

But Botha will appeal the ban at a hearing in Adelaide on Monday.

Botha was cited on two separate code of behaviour counts from SA’s tense draw with NSW at Adelaide Oval, which ended on Thursday night with the hosts narrowly failing to secure a final berth.

The former South African international copped a reprimand for using “obscene, offensive or insulting” language during NSW’s first innings.

More seriously, he pleaded guilty to a charge laid by umpires which related to “repeated inappropriate conduct relating to the condition of the match ball”.

For that offence, he was suspended from the next Shield game – a penalty he disputed but the ban was upheld after a post-match code of behaviour hearing.

The charge is believed to relate to Botha’s actions after taking a second new ball in NSW’s second innings.

He is believed to have used spikes on his shoes to tamper with the old ball, which he then threw away.

Botha declined to speak to media after SA came within one NSW wicket of winning and securing their spot in the Shield final, but coach Darren Berry said the captain was “emotional” in the changing rooms.

The Blues’ last three tailenders survived almost 20 overs and NSW were nine wickets down at stumps.

The draw meant SA joined Western Australia and NSW atop the ladder on 26 points entering the last round of matches. Queensland (22 points) can also make the decider.

Botha’s ban continues a troubled season for the 31-year-old.

Last October, he was cleared by Cricket Australia of having an illegal bowling action after being cited by umpires in a limited-overs match.