More bones have been found in Queensland's Gold Coast seaway as authorities scour the area for what they suspect are human remains.

Recreational diver Drew Valentine discovered what was believed to be a human bone in the previous week. After handing the first bone he found to police, he found a second bone after diving into the south wall of the seaway. Mr Valentine thought both of the bones might have been in the water for years. He added that the water comes in and out of the area. He said he saw many rock cabins underneath. Any object might have been trapped under the rock cabin, and the water might have pushed it out.

The suspected human remains have been sent for analysis at the John Tonge Centre in Brisbane. According to Senior Sergeant Lucas Young, police divers have since retrieved two more bones while searching near the southern sea wall on April 24.

A few days ago, Young said they have yet to confirm if the bones are part of human remains. He said the results of bone examination may take several days.

A total of four bones have been found and one of the bones has been confirmed by forensic tests as not human. Forensic experts have declared that the first bone found by Mr Valentine was a human thigh bone. The second bone found by the same diver, which was suspected to be from a human, turned out to be negative during testing.

Young said the bones found by police divers could be scraps or lamb shank bone. The smaller of the two bones was a mystery to authorities since they have no idea what it is.

The sergeant said the confirmed human thigh bone could be the key to closing a missing person's case but it was too early to tell to whom it belongs to. Young told reporters the discovery may bring closure to a family looking for a missing loved one, and that kind of result is what the police was always after.

Reports said it was unclear if the thigh bone belonged to a male or female or how long it stayed underwater. Solving the mystery of the bones could open a new investigation.