Papua New Guinea and Fij have refused to join the Australia and New Zealand-led agreement, which has been signed by most other Pacific nations.
Wadan Narsey, a Fijian economist at Australia's Swinburne University, said the absence of Fiji and PNG was a setback but he said there were still advantages.
He said the first of these was that something was better than nothing.
"Second, I think once you have an agreement in place there is a lot of scope to building on it in the future and there are many possible benefits especially with respect to labour mobility which is providing unskilled labour for all those areas where Australia and New Zealand have those periodic labour shortages."
Mr Narsey said Australia and New Zealand may be enticed to make more concessions to try and bring PNG and Fiji into the deal.
Photo: Supplied Wadan Narsey