Tony Abbott is known for his bizarre on-camera antics, but his latest may be the strangest yet.

The former Australian Prime Minister was at Parliament House in Canberra on Wednesday (local time) for a portrait unveiling of another previous Prime Minister, Julia Gillard.

The two politicians are long-time rivals, with Ms Gillard accusing Mr Abbott of misogyny in a now-famous speech in 2012.

Mr Abbott was one of a group of well-wishers waiting onstage to congratulate Ms Gillard as her portrait was revealed. Video shows him remaining alone on one side of the stage as she posed for photos and chatted with several other people.

Rather than join the conversation or step off the stage, Mr Abbott remained standing rigidly still, staring at Ms Gillard with his hands in his pockets.

Footage shows that he remained absolutely still for an entire minute, seemingly untroubled by the large audience watching him.

Some on Twitter speculated he was simply waiting to congratulate Ms Gillard, while others joked he was "either rebooting or in standby mode".