A police manhunt is underway for two men believed to be involved in a fatal shooting on the New South Wales Central Coast.

Emergency services were called to Warner Avenue in Wyong just before 12:30pm, following reports of shots being fired.

A 22-year-old man was treated by paramedics, but died at the scene.

Another man, aged 28, was taken to hospital with a gunshot wound to his hand.

Acting Superintendent David Waddell, from Tuggerah Lakes Local Area Command, said both men were in a vehicle when they were hit.

'Some kind of altercation took place'

He said police believed the shots were fired from another vehicle driving past, with at least two people inside.

"We believe it's isolated ... some kind of altercation took place between the two parties in those two vehicles, but what exactly led to it and whether there was any background, I couldn't say," he said.

Police are searching for the two men in the vehicle, which was only described as white.

Two crime scenes have now been established.

Police established a crime scene at Warner Avenue in Wyong after the fatal shooting on July 3, 2017. ( ABC News: Ewan Gilbert )

The first surrounds Byron Street, where police believe the shooting happened.

The second — about 500 metres away on Warner Avenue — is where the victims and their car were found by emergency services.

Acting Supt Waddell said local police and the homicide squad were thoroughly investigating the shooting, and appealed for further information.

"Hopefully we'll get assistance from members of the public ... we are calling for information ... it's very early days in the investigation," he said.