The Pacific Network on Globalisation, or PANG, says discussions around enhancing the Pacific Agreement on Closer Economic Relations are not truly regional following Fiji's withdrawal from them.
Fiji announced last week it would not be party to PACER-Plus amid problems within the Pacific Islands Forum.
Fiji has been excluded from numerous PACER-related discussions after it was suspended from the Forum in May.
Fiji's interim regime says it has exhausted means of redress for its exclusion and is now seeking remedy from the Vienna Convention.
PANG's Maureen Penjueli says more needs to be done to bring Fiji back into the fold.
"Fiji's the second largest economy in the region. Its exclusion from probably the most important trade deal in the region simply doesn't make sense at all. And I think Fiji's grievances [over exclusion] need to be resolved. Some of the signals from the other parties to PACER are positive."