Bradley Ambrose recorded what was said by the National Party leader and ACT's Epsom candidate when the pair met in an Auckland cafe last Friday.
Mr Ambrose's civil lawyer Davey Salmon, says a teleconference was held with a judge on Friday afternoon and a hearing has been scheduled for Tuesday morning in the High Court at Auckland.
He says John Key, the Attorney-General, TV3 and the Herald on Sunday were also represented on the phone call.
A spokesperson for the Solicitor-General has confirmed he will be in court on Tuesday to represent the Attorney-General, but wouldn't reveal what role he will play in proceedings.
Mr Key has laid a complaint against Mr Ambrose, claiming the conversation with Mr Banks was illegally recorded.
Mr Ambrose's criminal lawyer Ron Mansfield told Morning Report in no way can the discussion be regarded as secret.
"What took place wasn't a private communication. What we say it was was a public event where media were invited along to for political gain for those who were holding it," he says.
Mr Mansfield says his client has been described by politicians as unethical and is considering suing for defamation.
He says the controversy is affecting Mr Ambrose's work prospects.
Police demands questioned
Police are demanding Radio New Zealand and three other news outlets hand over unpublished material and other information relating to the recording and say search warrants are likely to be issued.
Wellington media lawyer Peter McKnight told Morning Report that is a new step for police.
He says they will have to convince a district court judge to issue the search warrants.
Victoria University law lecturer Steven Price told Morning Report the police are taking an extreme measure.
The concerns are shared by the International Federation of Journalists, which is condemning the demands made by police.
The federation's Asia-Pacific director, Jacqueline Park, says there are ethical questions about how the recording was made but the police action could be interpreted as an attempt to suppress media freedom.