The Australian Senate has voted against answering questions about the video-surveillance system known as TrapWire.

Greens Senator Scott Ludlam asked the Senate today to question the government on whether TrapWire is being used locally. His motion was denied, however, without calling for a division of the assembly.

Following the vote, Ludlam addressed the Senate, expressing his bafflement over why the motion was denied.

"It simply asks — yes or no — whether these systems are deployed anywhere in Australia. It doesn't make any accusations. We don't even have a clear idea of exactly what this pattern-recognition surveillance system does, but I'm seeking to ascertain whether or not it is used by any Commonwealth agency.

"I would have thought that was a fairly straightforward request."

The issue does not appear to be over, however, with Ludlam reinviting the government to address the chamber on the issue "so that we don't have to use other mechanisms".

These include seeking answers from the Attorney-General, Defence minister and Home Affairs minister.

"The Government could have done this the easy way. Instead, we will have to submit formal questions on notice to the Federal Police, ASIO, Customs and Border Protection, the Department of Defence, and the Australian Quarantine and Inspection Service," Ludlam said in a statement.

"All we want to know is whether the system operates here. The questions I submit to each agency will go to whether the TrapWire system is deployed in Australia, or if its use is under consideration."