Tonga's minister for Public Enterprises says the Public Servants Association hasn't officially confirmed its agreed to talks, scheduled for Thursday.
Afu'alo Matoto says he sent a letter last week asking for the PSA to confirm this week's meeting, but they haven't.
The PSA has been been threatening industrial action, if a meeting with the government wasn't held to discuss concerns the union has been raising for several months.
The union's grievances centre on what it says is the failure of the Government to abide by the terms of a memorandum of understanding signed to end lengthy public sector strikes two years ago.
He says the PSA should also stop making threats, prior to any discussion with the government.
"Well I think its really up to the PSA if they want to talk. Because all I need is the confirmation from them that they will restrain themselves from issuing these threats and demands and so on, until we have talked and we see what the outcome of our talks will be, and we can sit down and talk."
Tonga's minister for Public Enterprises, Afu'alo Matoto.
The union has questioned the government's long term commitment to pay rises given at that time and has raised objections to the way widespread redundancies were implemented in the public service last year.