A community group known for its opposition to the development of a Walmart store in Atascadero intends to sue the city, according to documents filed Monday in San Luis Obispo Superior Court.

Save Atascadero plans to contest the legality of the city's June 26 approval of the much-discussed Walmart project at Del Rio Road and El Camino Real.

Litigation could push construction of the new shopping center by a year or more, city attorney Brian Pierik said Tuesday.

Before the filing, the store was slated to open as early as 2014.

The local group plans to challenge Atascadero’s approval of the project, including the city’s certification of an environmental review on the shopping center along with related development plans and permits, court documents stated.

The city had not been served with the lawsuit as of Tuesday night, Pierik said.

Once the city has received the lawsuit, it would then be reviewed and attorneys on both sides would enter into court briefings before a hearing would be scheduled, he added.

Save Atascadero, previously called Oppose Wal-Mart, is a local group led by Atascadero resident and group spokesman Tom Comar and group coordinator Lee Perkins.