Investigators searching a NSW creek where half a human body was found have located another body part, police say.

The lower half of a man's corpse was found by a family in an isolated creek on a private property at Dairyville, west of Coffs Harbour, about 4pm (AEDT) on Sunday.

Since then, police have been searching for the rest of the body, which is believed to have been washed to the area by recent heavy rains.

On Tuesday afternoon, a "suspected" human body part was found.

"The body part has been sent for forensic examination. At this stage it is unknown whether the part is human or not," police said in a statement.

Police are treating the man's death as suspicious and continue to search the creek and its banks.

On Monday, Superintendent Mark Holahan said the body, which was severed at the waist, was not clothed and was found with no other items.

"It was in a state of decomposition," Supt Holahan said.

"What we are saying, without any formal forensic testing, is that it hasn't been there for months, it hasn't been exposed to the elements for months before being found."