Limit Cuerden says traffic measures around the Lancashire Central site in South Ribble will be inadequate and the development will cause congestion and rat runs.
The group has reiterated its fears as works have recently started at Lancashire Central, formerly known as the Cuerden Strategic Site.
Representative John Jones says further strain will be placed on local roads, such as Lostock Lane, despite filter lanes and roundabout changes at nearby junctions.
And residents are becoming increasingly frustrated that their concerns have been “overlooked from day one.”
He said: “It’s going to ruin South Ribble, the road network is inadequate for a development of this size and it’s not going to work.
“It will go from one of the best places to live to one of the worst because of the grid lock.
“It’s not just Ikea, it’s office spaces and hundreds of homes.”
He has called for an additional entrance to the site to be considered.
Authority bosses say the plans were scrutinised during the planning process and community consultation events have taken place.
The Ikea store will be built on a site at the end of the M65 between Lostock Hall and Farington and work is underway on a construction traffic link with the M65.
The site is predicted to deliver 4,500 jobs and an estimated Â£240m annual boost to the local economy.
A spokesperson for Lancashire Central said: “The local Highways Authority and Highways England have closely scrutinised the development during the planning process, including rigorous assessment of site accesses.
“A substantial range of highways improvements will be delivered as part of this development, specifically designed to increase highways capacity. These include significant changes to the M65 terminus roundabout.”