New Zealand's proposed revisions to the laws that govern its Government Communications Security Bureau have provided a venue for political theatre by Kim Dotcom, who choppered into Wellington to speak against the bill.

With only 15 minutes to speak to a parliamentary hearing into proposed spy laws in New Zealand, Kim Dotcom didn't have time to deliver much of substance, so the resulting political theatre shouldn't surprise anybody.

He fired off a tirade directed at the United States, New Zealand's spy agency the GCSB, and prime minister John Key.

The hearings cover the increasingly sore point of expanding the Government Communications Security Bureau's remit to allow it to spy on New Zealand citizens. Like spy agencies in many other countries, the GCSB is prevented by law from spying on locals.