Enterprise Minister Batt O'Keefe has said job losses at Quinn Insurance are likely.
It is reported the joint administrators appointed to the troubled insurer are seeking 800 redundancies.
Minister O'Keefe said that while nothing has been officially confirmed, redundancies are likely.
But he denied the actions of the Financial Regulator in partially banning the company from doing business in the UK and the North are to blame.
"Liquidity was a problem within the insurance company itself," the Minister said. "The UK market was a loss-maker, and obviously there was a question of pricing policy into the UK."
"All of those had to be looked at."
Workers at the embattled insurer vowed today to fight any redundancy plans.
The plans, which will be discussed with staff tomorrow, could see about of a third of the firm’s 2,400-strong workforce lose their jobs.
It is understood the majority of cuts will be made at the company’s biggest centres in Dublin, Cavan, Navan and Enniskillen.
Staff are expected to be offered voluntary redundancy over a period of up to 18 months, with management seeking some redundancies in the shorter term.
Workers' spokeswoman Mona Bermingham said staff were extremely fearful for their futures.
“This is the first we’ve heard of it – we had been given no indication of numbers or locations,” she said.
“There’s a lot of worry, disillusionment, dejection – it’s going to have a massive impact.
“This is not something we’ll be accepting easily.”
Earlier this month, the High Court in Dublin appointed Paul McCann and Michael McAteer, of Grant Thornton, as permanent administrators to Quinn Insurance after Financial Regulator Matthew Elderfield raised concerns about its solvency levels.
The firm’s UK division was shut down but Mr Elderfield allowed it to reopen for some business last week while he liaised with the administrators about reinstalling other product lines.
Ms Bermingham called for more work to resume in the division as soon as possible.
“If more segments of the UK market reopened they could then reassess the job losses,” she added.
A spokesman for the administrators declined to comment on the redundancies and said staff would be the first to be informed at meetings in Quinn Insurance centres tomorrow afternoon.
“We are not communicating it to anyone until we communicate it to staff,” he added.
The Quinn Group employs more than 8,000 people across Ireland and the UK through the flagship insurance firm and cement, quarry, glass and property businesses.
Fine Gael called for the massive redundancy plan to be reconsidered and for a decision on reopening more UK business to be fast-tracked.
The party’s labour affairs spokesman, Damien English, Cavan/Monaghan TD Seymour Crawford and Meath East TD Shane McEntee said towns and communities with large Quinn workforces would be devastated.
In a joint statement, they said: “The sheer number of redundancies proposed will have a serious knock-on effect in these areas and job losses in other sectors are bound to follow.
“Reopening more sections of the UK market to Quinn would in turn save more jobs. Fine Gael is therefore urging him to fast-track a decision on these other products as soon as possible.”