One French farmers' union has branded a strike of milk processors "irresponsible" as organisations representing dairy farmers continue to clash over how to push for increased milk prices.

The strike, which began on 10 September and is being orchestrated by the Organisation des Producteurs de Lait (OPL), is in protest against the low prices paid to farmers and market deregulation.

According to the OPL, close to 40% of French dairy farmers are participating in the strike.

However national trade federation the FNPL, which is affiliated with powerful farmers' lobby the FNSEA, has estimated that only around 7% of producers are involved in the strike at a national level.

"The producers who are on strike are losing money they will not recover. It's irresponsible to lead them into this kind of action," it said in a statement.

So far, the strike has had a minimal impact on major processors such as Lactalis, which has  recorded a 4-5% decrease in milk supplies.