Biarritz president Jean-Baptiste Aldige said on Thursday he has no choice but to move the French Top 14 club from the town due to a lack of support from the local government.
Former Hong Kong full-back Aldige, along with now owner Louis-Vincent Gave, took over at the five-time French champions in 2018 and has threatened to take the team from the Basque Country almost 1,000km north to Lille on the Belgian border.
"We're escaping because we've given a death sentence here," Aldige told AFP.
"We're trying to look for welcome relief or somewhere that wants to give us the structures so we can live. Lille or somewhere else.
"Why are we in this position? Three years ago Biarritz were already dead. Rugby-wise we resuscitated them but they're still on an intravenous drip economically."
Aldige's plans to renovate the club's Parc des Sports d'Aguilera home and the area surrounding it have been blocked by the town's mayor and authorities in the greater urban area which includes Bayonne.
Biarritz beat their now second-tier Basque rivals -- only 5km separate their stadiums -- in a promotion play-off in June.
"We have inadequate structures for the season. A club has never started a Top 14 season with a Federale 3 (sixth-tier) stadium and no training complex," 37-year-old Aldige said.
"We did what he had influence over, the sporting side of things. On the other side of things nothing has been done by the local government with the structures."
This weekend, Aldige's side host Bordeaux-Begles in their first top-flight game since relegation in 2014 but they have the league's lowest budget at 13 million euros ($15.4 million).
"There's excitement about finally tasting the Top 14 which we dreamt about and worked on these past three seasons," Aldige said.
"We deserve it. And there's apprehension to play with the big boys which is a new experience for all levels of the club.
"I've been forced to do it on a shoestring budget. Imagine if I'd been given a stadium and a little bit of money."