A man's body has been found in a minibus in a car park in Sydney's south-west.

The grim discovery was made in a business park at Garema Circuit in Kingsgrove about 10.15am on Wednesday.

A police spokeswoman said the man's death appeared suspicious.

Police have established a crime scene and are continuing inquiries to determine the cause of the man's death.

Forensic officers examined the ageing blue and white minibus in the corner of the car park on Wednesday afternoon.

A worker said he had only noticed the vehicle on Wednesday morning and did not believe it had been parked in the car park for long.

The man has not yet been identified.

Police are asking anyone who was near the business park in the past 24 hours to contact them via Crime Stoppers on 1800 333 000.

With AAP