South Australian Opposition Leader Steven Marshall has defended his handling of the Troy Bell affair, blaming secretive state laws for not revealing earlier the allegations against the southeast MP.
Mr Bell quit the Liberals just over a week ago after it emerged he was facing serious theft charges following an investigation by the Independent Commissioner Against Corruption.
However, that resignation came some time after charges were laid while Mr Marshall made his first comments the following day, four days before Mr Bell's first court appearance last week.
Mr Marshall said he was prevented in speaking out sooner by the state government's secretive ICAC laws.
"We have the most secretive ICAC in the country," Mr Marshall said on Sunday.
"I couldn't speak until I had authorisation from the ICAC commissioner."
Mr Marshall said to simply announce Bell's resignation would have allowed people to "join the dots" in relation to his position and the allegations against him.
"We couldn't do anything to identify Troy Bell. We didn't want to do anything that would prejudice the case," the opposition leader said.
Bell has been charged with 20 counts of theft and six of dishonestly dealing with documents related to the misappropriation of more than $2 million.
In relation to the 20 counts of theft, court documents allege Bell dishonestly dealt with money from the South East Education and Training Association and the Limestone Coast Education and Training Association between 2009 and 2012.
The six dishonestly dealing with documents charges relate to offences against the Millicent High School between 2010 and 2013.
The first-term MP said he would vigorously defend the allegations and would continue to sit in parliament as an independent.
But Treasurer Tom Koutsantonis has questioned his ability to properly represent his constituents.
"Troy Bell is going to spend the next seven months talking to police and lawyers, rather than advocating on behalf of the people of Mount Gambier," the treasurer said on Sunday.