By the time the Lawrence City Commission finishes its work tonight, another Wal-Mart lawsuit could be incubating.

The commission is expected to approve rezoning of land at Sixth Street and Wakarusa Drive where Wal-Mart wants to build, limiting the size of the biggest building on the site to less than two-thirds of what the retailer has proposed.

And that means a seventh lawsuit against the city is likely, a co-owner of the land said.

“This downzoning infringes — and infringe isn’t strong enough a word — significantly damages our property rights,” said Bill Newsome, who owns the property with Lawrence developer Doug Compton. “Litigation is an option we won’t have any choice but to pursue.”

Because of the six other lawsuits already pending in the matter, city officials wouldn’t comment directly on the rezonings.

But Assistant City Manager Dave Corliss said the city generally has authority to rezone property against an owner’s wishes, as long as the rezoning doesn’t interfere with the existing use of a property.

“The law represents a balance between a property owner’s interests in using a property the way they determine to be fit, and a community’s interests,” Corliss said.

The city, of course, has been able to prevent the “existing use” of a Wal-Mart since May by refusing to issue building permits for the project. The city about the same time initiated the rezoning, limiting the size of the biggest store on the site to 80,000 square feet — short of the 132,000 square feet that Wal-Mart wants to build.

Landowners attempted in 2002 to rezone the land for a bigger store — as much as 200,000 square feet — but were rejected by planning officials. Undaunted, they applied in May 2003 to build the 132,000-square-foot store under the zoning already in place.

The newest rezonings come without the recommendation of the Lawrence-Douglas County Planning Commission, which split, 5-5, on the issue last month. That split, plus a “protest petition” filed by Newsome and Compton, means the City Commission will need to muster a 4-1 “supermajority” to approve rezoning tonight.

That shouldn’t be difficult: The City Commission has voted unanimously in the last year on almost all matters relating to Sixth and Wakarusa.

Newsome noted the site’s current zoning had received approval from a previous City Commission.

“With this City Commission, process means nothing and binding approvals mean nothing,” Newsome said. “Anyone who owns property in Lawrence should be very concerned about what’s going on in this case.”

Mayor David Dunfield declined an opportunity to respond to Newsome’s comment.

The commission meets at 6:35 p.m. today in City Hall, Sixth and Massachusetts streets.