Carrefour has refuted claims from French grocery rival Casino that it approached the business over a possible tie-up.

Casino, which has suffered a share price slump this year amid concerns over its debt, said this morning that its board had met on Sunday and “unanimously decided to reject Carrefour’s approach”.

France’s fourth-largest grocer claimed it had been contacted by Carrefour but spurned its overtures.

Its board “reiterated its entire confidence” in Casino’s strategy and noted regulatory hurdles to any deal, given that Carrefour is France’s second-biggest grocery player.

However, Carrefour said it was surprised that Casino had met to discuss “a merger proposal that does not exist”.

In a terse statement, the retailer alleged that “difficulties” faced by Casino could have prompted the “misleading and groundless communications”.

Carrefour, which struck a buying alliance with Tesco earlier this year, is the world’s second-largest retailer by revenues – behind only Walmart – and holds 20.4% of the French grocery market.

Casino, in contrast, has a market share of 11.6% in its homeland.

It has been selling off non-core businesses in a bid to slash its debt pile, but continues to operate etailer Cdiscount and upmarket retailer Monoprix, which has struck a deal with Ocado to launch an online presence.