All the victims have been men talking to people based overseas.
A spokeswoman for the Waitakere police district, that covers west and north Auckland, said one case was reported earlier this year, but the probekm was not as widespread as in south Auckland.
"We are not immediately aware of cases in the past month fitting this description on the same frequency as Counties Manukau, but we encourage anyone who is a victim of a situation like this to contact police," she said.
And Auckland City Police spokeswoman said no cases had been reported in the district recently.
Detective Senior Sergeant Eddie Sutherland said people need to take extreme care when talking to strangers online.
"Anything communicated visually via the internet or mobile phone could potentially be published online," he said.
"People should not engage in any activity on the internet that they want kept private as they will make themselves targets for blackmail attempts.
"Keep personal information private, don't respond to messages from people you don't know, and don't post revealing pictures of yourself online."
Police were seeing a growing number of people putting themselves into dangerous situations when using other social media websites and apps, Mr Sutherland said.
"Often these victims will meet up with someone they have met online, only to end up being assaulted and robbed."
Lesser known sites tagged.com, badoo.com and sayhi.com were becoming popular targets, he said.
"Be aware that online profiles may be fake.
"If you are going to meet up with someone you met online then make sure someone knows what your plans are, and arrange to text them at set times. Meet in a public place and leave if you feel uncomfortable."
"Extreme care" needed to be taken online, Mr Sutherland said, and people should be wary of situations that "sound too good to be true".
