Up to 1,100 jobs are under threat at the business which in October last year revealed that it had accrued £1.1 billion of debt.
The London-based chain said its problems had been compounded by the coronavirus pandemic.
Bosses have now said that PizzaExpress will launch a company voluntary arrangement – allowing it to pay creditors over an agreed fixed period, enabling it to continue trading.
UK and Ireland managing director Zoe Bowley said that while the financial restructuring was a positive step forward, she and her team had been forced to make ‘some really tough decisions’.
‘As a result, it is with a heavy heart that we expect to permanently close a proportion of our restaurants, losing valued team members in the process. This is incredibly sad for our PizzaExpress family and we will do everything we can to support our teams at this time,’ she said.
‘As we continue to reopen our restaurants for dine-in and delivery, we will successfully navigate the extended period of social distancing expected in the months ahead and, in so doing, protect 9,000 jobs.
‘The initial signs from the restaurants that have been reopened have been very encouraging and we hope that our loyal customers continue to support us now more than ever.’
No decision has been made as to which restaurants will close but the chain has now been put up for sale.
Meanwhile, earlier this week it was announced that gym operator and sportswear retailer DW Sports had gone into administration.
However, it has now been confirmed that DW Health Club, based at St Brelade’s Bay Hotel, and the affiliated Fitness First Jersey, in St Helier, will be unaffected and will continue to trade as normal.
A statement issued by DW Health Club Jersey said: ‘As you will have seen in the news today DW Sports in the UK has announced that some of their clubs in the UK will be closing.
‘Please be assured that both Fitness First Jersey and DW Health Club Jersey are not affected by this in any way as we are entirely separate companies.’