Annabel Digance, 63, and her husband Gregory Digance, 60, entered not guilty pleas in Adelaide Magistrates Court on Wednesday.
They were remanded on continuing bail to appear in the District Court for arraignment in March.
The decision came after they failed to have the case against them thrown out as an abuse of process.
Ms Digance and her husband were arrested in April at their Strathalbyn home, south of Adelaide.
Police said previously it would be alleged they were involved in a common enterprise to obtain a personal gain by threatening to make allegations of misconduct against Opposition Leader Peter Malinauskas.
It was understood that benefit involved Ms Digance being placed in a winnable spot on the Legislative Council ticket or being preselected for a safe Labor seat prior to the next state election in March 2022.
In her application to have the case thrown out, Ms Digance argued that if any threats were made they fell within the so-called "political exception" to blackmail laws which protected "negotiations" to secure a political advantage.
She also noted that almost a year passed between when the alleged offences occurred and when she and her husband were arrested, arguing the timing was designed to stymie a parliamentary inquiry into bullying and intimidation in the Labor Party.
Ms Digance served in the SA parliament as the lower house member for Elder from 2014 to 2018, but lost her seat to the Liberals in the 2018 state election.
21°C