Two Aucklanders are reported missing tonight, and police are asking for help in locating them.

Irene May McDowell, 83, an elderly dementia sufferer, disappeared from her Epsom resthome about midday today, police said.

She is wearing a tracking device that police are following, however environmental factors are interfering with it, a police spokesman told NZPA.

Ms McDowell could be wandering the streets and be in a disorientated state.

She was last seen wearing a black and white cardigan with a white and orange T-shirt underneath and dressed in long trousers. She was carrying a black handbag and a green supermarket eco bag. She is Caucasian of slim build with short brown hair.

Police asked for anyone who spotted Ms McDowell, to please contact them immediately.

Police are also concerned for the safety of a man last seen walking towards a beach south of Auckland tonight.

Reuban Morrison, 35, abandoned his motorbike at Waiuku, 64km south of Auckland, police said.

Just over an hour later he was seen walking along Karioitahi Rd, toward the beach.

Mr Morrison is described as Maori, about 180cm tall. He is of solid build, has a full black beard with short black hair.

He was wearing a beanie, ridgeline dark green or black jacket, track pants and gumboots.

A helicopter and police search and rescue teams are scouring the coastline for him and have concerns for his safety, police said.