A police sergeant who died after his squad car crashed into a tree in the NSW Hunter Valley last night has been remembered as a highly respected officer and a loving father to two young sons.

Port Stephen area Sergeant Geoffrey Richardson, 43, was driving through Allandale on his way to help other officers in a pursuit when his car ran off the road and crashed into a tree about midnight.

He was the sole occupant of the patrol car and died at the scene.

Sergeant Geoffrey Richardson died in the Allandale crash.

Sgt Richardson is survived by his wife, a serving member of NSW Police, and two sons.

Police say Sgt Richardson put his life on the line countless times in order to protect others, and had won bravery awards for his tireless work.



A critical incident investigation is now underway to establish how and why the experienced police officer lost control of his car rounding a bend during a routine callout.



"At the moment we don't have too many details. It's all subject to investigation, obviously," Acting Deputy Commissioner Geoff McKechnie said.

A police officer has died after his patrol car crashed in the Hunter Valley last night. (9NEWS)

"The investigation will take some time, obviously, and we may have some further information we can provide at a later time.

Act. Dep. Comm. McKechnie said his thoughts were with Sgt Richardson's friends and family.



"He is a father of two young children, and his wife and family are currently being supported by extended family and colleagues of the officer," he said.



"NSW Police Force will ensure that all available welfare, support and assistance is provided to his family and his colleagues as we work through this tough period ahead."

The officer was on his way to assist his colleagues when his car hit a tree. (9NEWS)

Sgt Richardson was remembered as a dedicated police officer who provided 18 years of service, in a tribute statement released by the NSW Police Force.



"In every sense, he was a hard-working, highly regarded, popular and committed police officer, who will be sorely missed by the organisation he so ably represented and the communities he diligently served," the statement read.



"Above all else, he was a loving and much-loved husband and father.

The 43-year-old sergeant died at the scene. (9NEWS)

"His wife, Senior Constable Margaret King, and his two young sons, are naturally devastated, and we ask that their privacy be respected during this extremely difficult time."



"As the men and women of this organisation always do in times of tragedy, we will band together and support Sergeant Richardson's family, his friends, and each other, through this extremely difficult situation."

The full NSW Police Force statement is below:

The NSW Police Force lost a highly respected and much-loved member of its family last night.



Sergeant Geoffrey Richardson from the Port Stephens Local Area Command was killed when the police car he was driving crashed into a tree on Lovedale Road, Allandale, around 11.50pm yesterday (Saturday 6 March 2016).



At the time, Sergeant Richardson had been driving to assist colleagues who were engaged in a pursuit. He was the only person in the car at the time of the crash.

Further police and Ambulance Paramedics were called to the scene, and got there a short time later, however Sergeant Richardson had passed away before their arrival. He was the sole occupant of the vehicle.



The matter is now the subject of a Critical Incident Investigation, which will be supported by the Newcastle Crash Investigation Unit and overseen by the Professional Standards Command.

Sergeant Richardson graduated from the NSW Police Academy in 1998. He served the Campbelltown Local Area Command as a Constable until 2005, when he was transferred to Cobar and promoted to the rank of Senior Constable.

In April 2010, he was transferred to Central Hunter Local Area Command, before moving to Lake Macquarie Local Area Command upon his promotion to the rank of Sergeant in December 2010.

He served Lake Macquarie until July of 2015, at which time he transferred to Port Stephens Local Area Command.

Sergeant Richardson provided 18 years of dedicated and distinguished service to the people of NSW. He was the recipient of numerous awards, including a Regional Commander’s Commendation for Bravery after he arrested a number of offenders while off-duty at Nelson Bay in 2012.

In every sense, he was a hard-working, highly regarded, popular and committed police officer, who will be sorely missed by the organisation he so ably represented and the communities he diligently served.

Above all else, he was a loving and much-loved husband and father. His wife, Senior Constable Margaret King, and his two young sons, are naturally devastated, and we ask that their privacy be respected during this extremely difficult time.