After a five-hour hearing, the Alexandria Planning Commission voted unanimously early Wednesday to push the city’s waterfront redevelopment plan forward by endorsing the plan passed by the City Council 13 months ago, and making changes in the zoning law.

The commission accepted the City Council’s request for a set of “do-over” votes, which council members openly hope will undermine lawsuits which have stalled development along the Potomac River in Old Town Alexandria. They described the changes as cleaning up “ambiguities’’ in zoning law.

But some residents called the plan a “leveraged buyout of the waterfront” for commercial interests. One of the major landowners in the area is the Washington Post Co., whose Robinson Terminal warehouses bookend the eight-block area and are for sale.

The zoning law changes, protesters said, will foil their ability to force a super-majority vote of the City Council when nearby residents object to changes in zoning-law language.

“The City Council could have proposed this” themselves, said Bob Wood, former member of the city’s waterfront work group which sought compromise on the city’s original plan. “You have been enlisted as an appointed, not elected, body to give them cover.”

City staff said the law was intended to restrict the super-majority demand only to protests affecting changes in the zoning map, but the city’s Board of Zoning Appeals disagreed last spring. The city itself is suing the BZA over that decision. That case is due to be heard by the Circuit Court in early April.

The council plans to take up the same proposals March 16. Because there has been turnover on the council since the last waterfront vote, the plan is likely to pass with a super-majority, or at least six votes.