More than a hundred Frankie & Benny's and Chiquito restaurants could be closed, according to their owners.
The Restaurant Group, who own the chains, said it is looking to exit a number of sites to stabilise its long-term future after posting hefty losses.
The company, who recently acquired Wagamama , posted an £87.7m pre-tax loss in the six months to June 30, falling from a £12.2m profit in the previous year.
The business has identified 42 sites it plans to exit, in addition to 76 Frankie & Benny's locations it earmarked in March this year.
It is unclear which locations have been earmarked for closure, but the group said they would allow leases to run out at "unattractive" current locations over the next several years.
Frankie & Benny's currently operate at three locations in Cardiff , two in Swansea and Wrexham, as well as Bridgend, Merthyr Tydfil, Llanelli, Nantgarw, Carmarthen, Llantrisant and Newport.
There are also Chiquito restaurants in Newport and Llantrisant.
A spokesman for The Restaurant Group said the company expected to exit at least 50% of their 352 "leisure sites" when they reach their next exit date.
He said approximately 88 locations would close over the next six years, with a further 88 sites with longer remaining leases closing after that date.
A statement read: "In our half year results we announced to the stock market today, we stated that the backdrop remains challenging for our leisure division, comprising principally Frankie and Benny’s and Chiquito’s.
"Responding to these headwinds in the casual dining market we stated that we expect to exit at least 50% of leisure sites reaching their next exit date.
"We want to stress that we are by no means committing to the closure of all these sites and certainly not with any immediacy.
"Our leisure sites have an average of six years to their first potential exit date, so as and when leases do come up for renewal, we will take a considered and disciplined approach, on a case-by-case basis.
"When and if we do close sites we will always look to redeploy staff to other sites within our portfolio."
