An impassioned defence for why Australian internet providers should be required to hand over the details of customers alleged to have illicitly shared the Oscar-award winning Dallas Buyers Club movie online has been launched in Sydney's Federal Court as part of a landmark online piracy case.

Michael Wickstrom, vice president of royalties and music administration at Voltage Pictures, the parent company of Dallas Buyers Club LLC, was the second witness called on the second day of a two-day preliminary discovery hearing that will determine whether Australian internet providers iiNet, Adam Internet, Dodo and others will have to supply details of customers who Dallas Buyers Club alleges infringed on its copyright.

Expert witness Daniel Macek of Maverick Eye UG, left, and Michael Wickstrom of Voltage Pictures leave the court on Wednesday. Credit:Ben Grubb

Mr Wickstrom appeared before the court on Tuesday, but was cross examined again on Wednesday, when he rejected an iiNet lawyer's suggestion that letters Voltage Pictures had sent to alleged pirates in the United States, after obtaining their details through US courts, were "threatening".