OTTAWA - The country's biggest civil service union is back at the bargaining table with the federal government this week in what it calls make-or-break contract talks.

The negotiations centre around proposed changes to sick leave for about 80,000 workers, but also focus on wages.

The Public Service Alliance of Canada says the relationship between the government and public servants has been damaged recently by the debacle with the Phoenix pay system, which has resulted in thousands of government workers being improperly paid, or in some cases not paid at all.

Treasury Board negotiators have been holding firm on a proposal to replace the existing sick leave system with a new short-term disability plan.

But PSAC says the proposal would force workers to choose between a pay cheque and going to work sick.

The talks have been going on for more than two years.