Marsh is suing its former SA manager of strategic risk Noel Vickery, claiming he took information from the company when he left after being made redundant.

Mr Vickery worked for Marsh from 2004 to February 2012. Later that year he went to Arthur J Gallagher Australia.

Federal Court Justice Anthony Besanko says Marsh alleges Mr Vickery used the information for his own benefit or that of Gallagher. Mediation has failed and the case is heading for trial.

Marsh has served Gallagher with a subpoena to produce documents for the case, and Justice Besanko this month made orders about what must be handed over. Earlier this year the two companies held talks and agreed to a subpoena concerning documents.

Gallagher produced 53 volumes of material and a laptop hard drive, but the court heard another 66,000 emails from Arthur J Gallagher in the US – filling 230 volumes – might be covered by the subpoena.

Gallagher complained compliance would be “oppressive”.

Justice Besanko says when Gallagher agreed to the terms of the subpoena it underestimated the amount of work involved, but he is not satisfied that parts of the subpoena are oppressive.

The case continues.