There have been reports that an analyst for ING said both companies had contacted project owners over the defect, which supposedly affected 20% of turbines and would cost €20,000 per blade.
The component in question is the 'blade route insert' attaching the blade to the hub and was manufactured by Vestas.
In response, Vestas said the ING analyst's assertions surrounding the 650kW turbines were incorrect. A spokesman said the price tag was wrong and that only 4% of its 4,200 V47 turbines were affected. It also said it has been working on the problem since 2010.
Gamesa, whose G-4X turbine also uses the component, said: "Gamesa has known about a failure on one of the components incorporated in the G4X by mean of its own customers, which apparently were informed by the manufacturer in charge of its design and supply."
The company said it has had offered to inspect its fleet of G4X turbines to determine the extent of the problem.
There have been issues with the V47 in the past. In 2008, a 23-metre blade came off an eight-year-old V47 installed at Windpark Tuitjenhorn in the province of Noord-Holland.
During the failure, a section of the blade landed on the nearby N245 road between the villages of Oudkarspel and Dirkshorn in the community of Harenkarspel. With the road quiet at that time of night, no one was hurt, but the road was closed for some time.
The V-47 model, is a modified Vestas V42, with a longer rotor diameter and different blade profile. The first turbines came into service in the late 90s.