An unmanned car has ended up on its side in a Tauranga estuary after rolling about 50m down Maxwells Road.

Emergency services were called to Maxwells Rd about 11.30am after reports of a car in the harbour.

The red Toyota on its side. Photos" Letitia Atkinson.

A reporter at the scene says the red Toyota has rolled about 50m down the hill, over the curb and into the estuary, taking out part of a fence in the process.

Tauranga Police Constable Ian Sadler says there was no one in the car at the time and it appears to be either handbrake malfunction or someone forgetting to put the handbrake on when parking.

Police remain at the scene speaking to witnesses about what happened.