Police say they are baffled by the death of a Brisbane school teacher they believe was kidnapped before he was fatally hit by a truck on the Pacific Highway in northern NSW.

Emergency service crews were called to Cudgera Creek, south of Tweed Heads, just after 7am on Monday, and have since identified the deceased as 43-year-old Anthony Stott.

Detectives later arrested a 38-year-old woman and a 46-year-old man, who have been charged with detaining a person with intent to obtain advantage.

Police are now appealing for further information on the case, which Tweed/Byron District Commander, Acting Superintendent Brendon Cullen described as "extremely unusual".

"It's … quite baffling really to understand how the man from Brisbane would end up down here in these circumstances and now we find that he's passed away," he said.

"We are very keen to find some answers and give some answers to the family involved.

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A police roadblock near Cudgera Creek, where Mr Stott died. Photo: ABC

Acting Superintendent Brendon Cullen said any information was important at this early stage of the investigation.

"Anthony had only just returned to the country from a trip in Peru, landing in Sydney earlier last week, then at Brisbane Domestic Airport on Sunday afternoon.

"We have recovered his vehicle, which was located abandoned near the scene on the M1 about 2am on Monday morning.

"We're also wanting to speak with anyone who may have seen his vehicle on Sunday afternoon — a silver BMW with NSW registration ANL 72Y."

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Police want to hear from anyone who saw Mr Stott's vehicle. Photo: NSW Police
Police allege victim was 'tied to a chair'

Acting Superintendent Cullen said the truck driver was extremely shaken by the incident.

"It took the truck driver by surprise and it is particularly traumatic for the driver," he said.

"The full circumstances are a little bit unclear as to how he came to be on the motorway and again if there are witnesses that may have seen anything we ask them to come forward.

"We still hold that crime scene and we are still processing that crime scene.

"Until that is completed, the matter is before the court.

"We believe he was tied to a chair within that house."

The pair charged have been refused bail and are scheduled to appear in court next week.

-ABC