The warning was delivered by the Indonesian Foreign Ministry's Director General of Asia-Pacific and African Affairs, Desra Percaya, at this week's MSG leaders summit.
The summit was hosted by Papua New Guinea's prime minister Peter O'Neill in Port Moresby.
It was attended by leaders and officials from the other four full MSG members: Vanuatu, Solomon Islands, Fiji and New Caledonia's FLNKS Kanaks Movement.
Indonesia, which is an associate member, was represented by Mr Percaya who endorsed the MSG's plan on regional co-operation and common prosperity.