A man has been charged with two counts of murder and one of attempted murder after incidents at two properties on Auckland's North Shore.

The 41-year-old is due to appear in the North Shore District Court on Wednesday morning.

Police were called to Seon Place in Birkdale shortly after 8.20pm on Tuesday after reports someone had been stabbed. They found a man with "moderate injuries".

The alleged offender was arrested at the same address.

"While speaking with this male, information has prompted us to dispatch a unit to a property at Lingfield Street in Glenfield to conduct a welfare check," police said in a statement.

A man and a woman were found dead at the second address.

A scene guard was in place at both scenes and police would be conducting exmainations over the coming days.

St John told RNZ it responded to the Birkdale address with an ambulance and a critical care unit around 8.25pm.

A person was taken to North Shore Hospital in moderate condition.

They were called to the Glenfield address at 8.50pm and were still at the scene shortly before 10pm.

"This is an awful set of events. I know this will leave many in our community unsettled, but what I can say at this early stage of the investigation is that the offender and victims are all known to each other," Acting Detective Inspector Megan Goldie said.

While there would be an increased police presence around Birkdale and Glenfield, there was no ongoing threat to the wider community, she said.