Crown Law will take over the prosecution of John Banks on a charge of knowingly filing a false election return.
Private prosecutor Graham McCready received a letter today from Solicitor General Michael Heron confirming he would intervene in the case.
The letter said the Solicitor General would assume responsibility, and asked for all relevant documents to be forwarded to the Crown Law office.
Banks was committed to trial following an oral evidence hearing at Auckland District Court earlier this month.
Mr McCready said the prosecution was taking a toll on his health, and appealed for the "full resources of the crown" to be put behind the prosecution.