Fiji's interim government says as the Republic of Fiji is a sovereign government it has a right to assert control over its borders.
Spokesperson Sharon Smith Johns says the government's position has not changed, despite the union leaders' decision to head to Fiji.
She says they will simply be denied entry at immigration, and will have to stay in transit to be placed on the first available flight out.
She says the situation is regrettable given the government's earlier openness to the delegation's visit.
Ms Smith Johns says the situation is entirely due to what the regime calls the group's obvious bias and unwillingness to engage in an open and fair way.