Police are warning people using a popular North Shore track to go in pairs and carry a phone after a man made lewd sexual remarks to a woman out on a walk.

The lone walker detailed the frightening encounter on a public Facebook page, saying she was approached by a man in an isolated spot on the Long Bay to Okura River Coastal Track on Tuesday afternoon.

She said as he walked passed he made a sexually-explicit remark before turning around and approaching her and continuing to make obscene suggestions. After pulling out her phone and telling him to back off he fled when another man appeared on the track.

The woman described the man as a slimly-built Caucasian with blonde hair. She thought he was aged in his late 20s or early 30s.

Police are now appealing for anyone who may have been approached the man or witnessed similar behaviour in the area to contact them immediately.

Waitematā East area commander Inspector Simon Walker said police received a report of a man acting suspiciously along a walking track in the Long Bay Regional Park at around 4pm.

Walker said the man had reportedly made comments of a sexual nature towards a woman before walking away.

The woman called police who conducted area inquiries to find the man. At this stage he had not been located, said Walker.

In general police advised people that it was safer to exercise with another person or group, carry a phone and share details of where they intended to go and how long they expected to take.