Quinn Insurance has announced that the Financial Regulator in the Irish Republic has allowed it full access to the UK car insurance market.
Last month, the company was put into administration and banned from doing business in the UK because of concerns about its solvency.
On Thursday it was announced that 800 jobs would be lost at the firm, with 200 of those redundancies in NI.
Just over half of Quinn's 1.3m customers are based in the UK.
The regulator partially lifted its ban earlier this month, allowing the firm to offer cover for provisional drivers.
The move to allow it to issue cover to full licence holders comes after meetings of committees of both the Irish parliament and the Northern Ireland Assembly on Thursday.
Both committees subsequently urged the regulator to allow Quinn back in to the UK market.
A statement from the Quinn Group on Thursday evening said permission to re-enter the UK car insurance market had come with conditions.
The statement said: "The re-entry into full licence drivers incorporates significant pricing changes which we believe will lead to significantly lower volumes than were previously written by QIL (Quinn Insurance Limited) in the UK private motor market.
"Nonetheless this is an important step in the process of ensuring the return of QIL to a sound financial and commercial footing."
Quinn, which also offers other insurance products including professional liability cover, said it was continuing to work with the regulator "in relation to the potential of reopening other business lines".
Earlier on Thursday, the administrators of Quinn said it would make 800 staff redundant, 200 of those in Northern Ireland.
It is part of their plans to downsize the firm, and affects about one third of the staff employed by the company on both sides of the border.
About 200 will go from the company's operations in Enniskillen and Derrylin leaving a combined workforce of 450.
The remaining jobs will go at the offices in Cavan, Navan, Dublin and Manchester.
It is believed the administrators, now running the company, hope the redundancies will be voluntary and take place gradually.
Quinn 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 and it's not something we'll be accepting easily."
On Thursday, a committee of the Irish parliament backed calls by employees to allow the company more access to its markets in the UK.
Five members of the workers' action group told the Enterprise, Trade and Employment committee that the company is losing 2,000 customers a day in the UK.
In Northern Ireland, the Assembly committee on Enterprise, Trade and Investment met with the administrator.
The committee says it also pressed for Quinn to be able to access UK markets.
However it said it had not had any discussions with the administrator about staff redundancies.
The firm's problem stem from massive losses made by its owner Sean Quinn in a stockmarket gamble on the now-failed Anglo Irish Bank.
Although the job losses will mostly be in the Republic, the restructuring relates primarily to Quinn Insurance Ltd's businesses in the UK.
Much of the UK business is handled by staff at Quinn's offices in Dublin, Cavan and Navan.
The details of the package to be offered to employees have not been revealed but it is understood workers will be offered more than the statutory redundancy.
In an email to staff the administrators said they were "extremely disappointed" that details of the job cuts had been leaked to the media ahead of an official announcement on Friday.