A Solomon Islands academic says the leaders of Melanesian Spearhead Group member states made a mistake in granting Indonesia associate member status in the group.
The five full members of the MSG are Papua New Guinea, Fiji, Solomon Islands, Vanuatu and the FLNKS Kanaks Movement of New Caledonia.
Tarcisius Kabutaulaka's comments come as another rift surfaces within the sub-regional group this time between the leaders of Fiji and Solomon Islands over the Indonesia issue.
The latest spat began with comments from Solomon Islands deputy prime minister Manasseh Sogavare saying Fiji should not have forced other countries to accept Indonesia.
Fiji's defence minister Ratu Inoke Kubuabola rubbished the claims, and pointed out that it was at a summit in Honiara in 2015 when Mr Sogavare was prime minister and chair of the MSG that Indonesia gained its current status.
Mr Kabutaulaka, who is an associate professor at the University of Hawaii's Center for Pacific Islands Studies, said since its inclusion Indonesia had not been shy about pushing its main agenda in the MSG.
In particular, he said Jakarta was suppressing the United Liberation Movement for West Papua which had observer status in the MSG and is seeking independence for the indigenous people of Papua from Indonesia.
Mr Kabutaulaka said despite Indonesia's claims to the contrary, it is not a Melanesian country.
"They should have denied Indonesia that membership. One of Indonesia's arguments is that it has the largest Melanesian population."
"In fact the Melanesian population in Indonesia is very small. First and secondly it is the most oppressed and is often not represented by the Indonesian government in the way that Jakarta is implying," he said.