He showed the other MPs how do it.
"I myself am Murray Pretoria ... which I think makes me sound like a South African spy, but that is me.
"So I invite other members of the House to have a think about where they are at in terms of their identity."
As the debate proceeded, MPs obliged. Labour's Palmerston North MP Iain Lees-Galloway said his spy name was Francis Robertson, and Te Tai Tokerau MP Kelvin Davis was Glen Leonard.
New Zealand First MP Denis O'Rourke wasn't playing ball. He did, however, reveal his favourite spy movie, The Third Man.
"This bill really conjures up all of those images that you see in that movie - the trench coat, the wide-brimmed hat, the dangling cigarette, and the muttered conservations in shady places."
He paused.
"It is very much like the way the National Party caucus works, actually."
Labour's David Parker preferred Frederick Forsyth's Day of the Jackal. Davis revealed he was a fan of Maxwell Smart, or Agent 86.
"I remember the time he was a bit distressed by the fact that his girlfriend, Agent 99, was paying too much attention to Agent 43, and she pacified him by saying 'Don't worry 86, you're worth two 43s'."
Minister for the GCSB and SIS Chris Finlayson, who is in charge of the reforms, then set about getting the discussion back on track.
The bill, after all, is arguably more significant than the 2013 reforms. It will allow the GCSB to spy on New Zealanders for the first time.
But first, Finlayson had to reveal his spy name: Francis Lohia. MPs agreed that was a pretty poor secret identity.
"I do not think that would work at all well," Finlayson admitted.
"But, anyway, back to serious stuff."