Key Points:

A 48-year-old man is in police custody after an armed offenders alert involving the man's estranged partner south of Auckland today.

About 20 armed police went to a semi-rural address east of the Papakura township about 10am after a report of a man holding up a woman with a rifle.

The police helicopter, Eagle, hovered overhead as armed police surrounded the house.

Senior Sergeant Shawn Rutene said no-one was hurt and the man was taken into custody without any difficulties.

"He virtually gave himself up to police. Police inquiries are continuing."

He said the man was likely to face charges and appear in court later today.

Armed police cordoned off streets surrounding the area and stopped traffic for about an hour and a half.