Pair of orca spotted under Mangere Bridge

A security guard came across an unlikely scene while taking a walk on his break - two orca swimming in the Manukau Harbour below him.

Nui Brown was on Mangere Bridge when he spotted the pair swimming underneath.

The guard described the experience as "exciting" and "surprising to people's eyes".

Although there has been numerous sightings of orca in the Manukau Harbour, this is the large mammal's first recorded visit to Mangere Bridge.

Orca specialist Dr Ingrid Visser says, despite how far the orca were spotted up the harbour, a visit is a normal occurrence of the killer whale.

"The location is the only atypical thing about this behaviour with New Zealand orca - they regularly go right up harbours, into the mangrove zones."

Dr Visser was alerted to the orca at the time, through her hotline 0800 SEE ORCA.

"They would have been in there hunting for stingrays."

Dr Visser recommends keeping your distance if you spot a killer whale, and not be "motivated by trying to get selfies".