The party plaza in front of the Metrodome is now Ground Zero in a legal dispute between the owners of the land and the Minnesota Sports Facilities Authority (MFSA), the public body overseeing construction of the new $975 million Vikings stadium.

Minneapolis Venture LLC owns the plaza that is home to the Downtown East light-rail station, as well as the spot where pre-game Vikings festivities are held. In a lawsuit filed last month, Minneapolis Venture called for a Hennepin County judge to clarify whether the land there and its underground parking garage are part of the stadium's broad reach.

Located along Kirby Puckett Way between Fourth and Fifth streets, the plaza is not part of the new stadium's actual footprint. But it's an important conduit to the light-rail station, downtown and a proposed public park west of the stadium. Negotiations have been ongoing between Minneapolis Venture and the authority, which wants to buy the land.

In a Tuesday letter to MSFA CEO Ted Mondale, an attorney for Minneapolis Venture claims the authority violated a 2003 agreement between the authority's precursor body and the city that permits pre-game festivities. In this case, the Vikings' Aug. 29 preseason game against the Houston Texans is part of the dispute. (The Vikings lost 27-13.)

The letter alleges that the authority failed to gain written approval prior to the festivities, and that use of the plaza began more than 24 hours before the pre-season game and continued 24 hours after the game, among other violations.

Said Minneapolis Venture spokesman Jon Austin, in an email statement: "As the Authority is well aware, it failed to seek (much less obtain) our written consent for its use of the Plaza last week, it set up on Tuesday for a Thursday evening game and has left its tents up through today and it failed to provide any proof of insurance for the vendors using the plaza. All of those actions are expressly detailed in the use agreement that the MSFA has chosen to ignore."

Minneapolis Venture has already threatened to cancel plaza activities for the final four games of the season and any post-season games -- because the current agreement expires Oct. 31.

The authority has said that Minneapolis Venture is "grossly" overstating the value of the land in an effort to squeeze millions as the stadium's groundbreaking nears. The new stadium is expected to open by August 2016.

In response to Tuesday's letter, Chair Michele Kelm-Helgen said all information that isn't already available on the authority's website will be forwarded to Minneapolis Venture "in a timely manner."

Janet Moore covers commercial real estate for the Star Tribune.