In a statement, Vestas said opposition groups were impeding access to the site. As a result, the project's lenders have agreed to delay forebearance agreement until 20 July, with the likelihood it could be extended further if certain milestones are hit.
Vestas has agreed to extend until 30 November. The delay does not affect its guidance for 2013.
The project is to be located in the Isthmus of Tehuantepec, in the La Ventosa region of Oaxaca, Mexico. The isthmus represents the narrowest piece of land separating the Gulf of Mexico and the Pacific Ocean.
Mitusbishi own 34% of Marena, with other investors including the Macquarie Mexican Infrastructure Fund and Dutch pension fund PGGM. In a statement, Macquarie said there was a chance the project could be axed if the issue is not resolved.
Opposition to the project first came to light last year when members of the local indigenous Huave community forced the mayor to destroy a building permit he had signed with developer Marena.
At the same time, a Huave Indian group in the neighbouring town of San Mateo del Mar issued a statement saying it will "take up arms" if the project goes ahead as planned.
Both events follow ongoing indigenous anti-wind protests that began late last year against the 225MW Piedra Larga wind farm, developed by Spain's Renovalia in Union Hidalgo, further north in Oaxaca. A man was shot dead, reportedly by a stray bullet from a warning shot.
Land rights clashes are central to the dispute, with landowners feeling duped by early land deals. In late October, Beatriz Olivera, head of charity Greenpeace's energy campaign in Mexico, warned: "Oaxaca wind development policy is unsustainable as it has violated elemental indigenous peoples' rights."