Police who were called to a burned out car near Havelock North didn't see the body lying inside.

Instead, the body sat in the car for another two days, as likely dozens of recreational walkers and cyclists went past, before it was discovered by a member of the public.

A police spokeswoman confirmed to Hawke's Bay Today the car engulfed by fire in the River Rd carpark was initially reported to police around 10am on Saturday morning.

Police conducting a scene examination on Tuesday which included officers combing through nearby grass and bush. Photo / Neil Reid

"Staff attended and due to the condition of the vehicle and debris from the fire, did not immediately identify that human remains were in the cabin of the car," the spokeswoman said.

"A subsequent inspection of the vehicle revealed suspected human remains."

The spokeswoman said a post mortem will be carried out on Tuesday and will assist police in identifying the deceased.

The investigation remained in its very early stages and staff were working to determine the timeline of events and circumstances of the death.

A woman walking her dogs in Havelock North on Sunday told Hawke's Bay Today she also had no idea there was a body in a burned out vehicle she noticed on the trip.

• 'The dogs were going crazy': Woman at river didn't realise body was inside burnt out car
• Body found in burnt out car

The River Rd carpark is a popular reserve on the Tukituki River and links to a walking area and the Hawke's Bay cycle trails.

The woman, who asked to remain anonymous, said her dogs realised something was off about the vehicle but she didn't think much of it.

"The car looked like a burnt out [shell] and the dogs were going crazy," she said.

A police examination recommenced at the scene on Tuesday morning, and included officers traipsing through grass and bush in the area.

Detective inspector David de Lange said in a statement the body was found in the vehicle in the car park on Monday.

Police have cordoned off the River Rd car park in Havelock North, where a body was found in burned out car. Photo / Warren Buckland

The death was being treated as unexplained.

"It appears the vehicle, which has been consumed by fire, has been parked in the reserve for several days."

A police forensics team at the River Rd carpark near Havelock North on Tuesday morning. Photo / Neil Reid

"While we are treating the death as unexplained, we are in the very early stages of understanding what has happened to our victim.

"The reserve is a popular area for cyclists and people walking dogs, providing access to the Tukituki River and adjacent cycleway."

Anyone with information which could assist the investigation is asked to contact police on 105 and quote event number P051805886.