But the big social media sites were not the worst offenders, he said.
"Today [Facebook's] behaviour is better than most. There's lots and lots of smaller sites and apps that people jump on that either have no particular concern for your privacy or will deliberately exploit your privacy for their benefit."
Sixty-one per cent of respondents used Facebook, up 7 per cent since the previous survey in 2012.
Of those, 77 per cent said they had changed their privacy settings, an increase of 3 per cent on the last survey, and 11 per cent from 2010.
The Privacy Commissioner, John Edwards, said that figure was encouraging. There were always risks when using sites that requested personal information, but the survey showed people were managing those risks.
The health sector was rated the most trustworthy, with 92 per cent rating health service providers as trustworthy.
Eighty-four per cent of the respondents thought the police were trustworthy, while 37 per cent trusted businesses trading online.
Top 5 privacy concerns
1 What children post on the internet.
2 Credit card or banking details being stolen.
3 Businesses sharing information without permission.
4 Identity theft.
5 Government agencies sharing information without permission.