WHEN police were called to reports of human remains found on a river bank they prepared themselves for a grim murder investigation.

But their CSI-style detective work has deepened the mystery - and questioned whether Captain Cook really was the first white man to set foot on the east coast of Australia.

The cold case began in November 2011 when a perfectly intact skull was found at Manning Point, near Taree, on the state's north coast.

Police were called in and an anthropologist said it possibly belonged to a young female. But further scientific testing - the results of which came back last week - revealed the skull to be a white male, with an 80 per cent chance of it dating back to the 1600s, decades before Captain James Cook arrived aboard Endeavour.

"The DNA determined the skull was a male," Detective Sergeant John Williamson said.

"And the anthropologist report states the skull is that of a Caucasoid aged anywhere from 28 to 65."

Human remains found in Manning River

The carbon dating results put the skull - dubbed Taree - as being from two time periods, the 1600s or late 1700s.

"It's fascinating," Dr Stewart Fallon, of Australian National University, said. "Using carbon dating on bone fragment and looking at enamel from a tooth, there are two possible time periods from when the person was around."

Dr Fallon said the first period would mean the male was born between 1650 and 1660 and died 40 to 50 years later. "The second period suggests the skull belongs to someone born anywhere from 1780 to 1790 and died between 1805 and 1810."But he said his data suggested there was an 80 per cent chance the skull came from the mid-17th century.

He said it was impossible to be more exact but he was carrying out his own tests to try to establish the geographical origins of the skull.

While fascinated, archaeologist and historians are cautious. "Before we rewrite the history of European settlement we have to consider a number of issues, particularly the circumstances of the discovery," renowned Australian archaeologist Adam Ford said.

"The fact the skull is in good condition and found alone could easily point to it coming from a private collection and skulls were very popular with collectors in the 19th century."

Taree man of mystery history

No other skeletal remains were found with the skull, making its origin debatable.

"Being found near a river bed after heavy rains means it could come from anywhere, even the remains of a relative stored on a farm. But having said that it warrants further examination and could be a significant find."

The fate of "Taree" is now in the hands of the NSW Department of Planning.

"The coroner has deemed that since the skull is over 99 years old he has no jurisdiction; it is covered by the Heritage Act it is considered a relic," Sgt Williamson said.

Australia And New Zealand Inside History editor Cassie Mercer said the find was exciting: "If the skull does pre-date British settlement, it may be a tragic yet fascinating clue to the little-known history of early interactions between First Australians and the outside world.

"It's intriguing the skull was discovered in NSW, far from the northern and western coastlines that have yielded archaeological evidence of interaction between indigenous people and Dutch, Portuguese, Javanese and Chinese traders."