Opposition politicians claim they have not had a say in the £3m purchase of a disused bus depot.
West Northamptonshire Council (WNC) has earmarked another £300,000 for legal fees and remedial work at the St James bus depot in Northampton.
The Conservative-run council said the site would be used to "deliver much-needed homes".
The Labour group leader, Wendy Randall, said an extraordinary meeting of the council should have been called.
The site on St James Road was once a tram depot, before becoming a bus garage in the 1930s.
That decade also saw the construction of an art deco building which still bears the name "Northampton Corporation Transport Offices" over the door.
The last bus left the garage in 2013 and the site has been disused ever since, although it was sold to the shoe company Church's some years ago.
A council spokesperson said: "To match market offers, WNC purchased the site at £3m, with a further £300,000 budgeted towards legal fees, stamp duty and future remedial work.
"Concerned that the site was heading for use as open storage, which we felt would not benefit residents, the council felt that it was essential to step in and acquire the site."
Ms Randall said: "I am very concerned to find that a decision has been made to use council money to buy the bus depot without consulting key stakeholders beforehand.
"All three councillors in that ward are Labour and were not asked for their opinion."
The opposition leader added that some of the councillors making the decision had served on the now-defunct Northampton Borough Council when it allowed Church's to buy the site, which she described as "the Tories cleaning up their own mess".
The Labour group said it was pleased to see the council had decided to create new housing at the site, which was "desperately needed in our area".
In response to the concerns about consultation, a WNC spokesperson said: "The leaders and deputy leaders of the three major political parties met to discuss the decision and process, and no objections were raised regarding either the decision or the process. An urgent decision was then undertaken to purchase the site.
"While the council recognises that this is not the usual process, this was a unique opportunity which had to be seized to ensure this large site benefits from considerate regeneration for the good of the local community."