The technology industry believes Facebook's largest ever hack is a wake-up call a lot of New Zealanders need.
Fifty million users were affected, at a time the company faces mounting criticism over issues including foreign election interference.
NZ Tech chief executive Graeme Muller says the hack is alarming.
"All of these big companies do a lot to look after security, but you can never rely on them. You need to take some ownership yourself and do some really simple things."
Mr Muller says the easiest thing people should do is change their passwords regularly.
"Once you're on the internet, it doesn't matter where you're living, it would be sensible to think about your security. This is a wake-up call for everyone."
Facebook says affected users have been asked to log out, and then log back in.
What happened?
Hackers stole digital login codes allowing them to take over nearly 50 million user accounts.
Facebook is yet to figure out whether the attacker misused any accounts or stole private information. It also hasn't revealed where the hacker was based, or why those particular accounts were targeted.
Chief executive Mark Zuckerberg described the incident as "really serious". His account was affected, as was chief operating officer Sheryl Sandberg's, a spokesperson said.
Experts say you should avoid using the same password on more than one site, because if one is hacked, it's easy for crooks to get into the other.
Here in New Zealand, Spark reset thousands of passwords last week belonging to people who'd used the same password on multiple sites, giving would-be hackers easy access.
Newshub.
