The Malcolm Turnbull-Bill Shorten show was the 10th most popular television program on Sunday night.
The first formal leaders' debate has widely been reviewed as dull and a dead heat between the prime minister and opposition leader.
Its five-city audience total of 529,000 was far short of the top ranking show, Seven News, which had 1.424 million viewers.
What's worse, when it ended after an hour there were only 93,000 die hards still watching.
Labor campaign spokesman Tony Burke told reporters in Canberra on Monday the debate would have been more interesting had it been more interactive.
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"I sat there. I'm enmeshed and engrossed by the policy detail," he said.
"But I'm not going to pretend that's a story for every Australian."
Coalition spokesman Mathias Cormann said the debate was aimed at "informing the public".
"People across Australia who watched the debate would have been better informed," he said.
Senator Cormann said it was useful to have a diversity of formats over the campaign.
