Former Communities Secretary Eric Pickles approved plans for the leisure facility, cinema, shops and restaurants in the north of the county in 2014 following an inquiry.
Northampton Borough Council objected at the time because authority leaders felt the development would affect trade in Northampton.
But subsequent applications have expanded the retail side of the Rushden development and a proposed garden centre has been replaced with a further “leisure facility.”
Now developers LxB Retail Properties have lodged yet another planning application to extend the retail area by a further 5,000 square metres.
Northampton Borough Council officers say the latest amendment is a step too far.
A report before the borough’s planning committee on Tuesday states: “The site has been subject to several amendments since the original permission in 2014, and the current proposal represents a further increase in the level of retail.
“As such, the council consider the development as proposed has the potential to lead to significant adverse impacts on the vitality and viability of Northampton town centre.”
Cabinet member for planning and regeneration at the council, Councillor Tim Hadland, said the council was committed to “protecting” Northampton town centre and will “challenge anything that threatens it, including the application for yet more out of town shops at Rushden Lakes.”
Marks & Spencer, Primark and House of Fraser have already signed up to Rushden Lakes, along with cinema chain Cineworld.
But the latest planning application proposes a repositioning of the previously approved “leisure terrace,” the extension of the previously approved retail terrace A, and the erection of new retail terrace, being called “terrace D” of some 6,500 square metres.
The borough council will make it’s objection to East Northamptonshire Council, which is set to decide on whether to pass the scheme.
While the objection is unlikely to disrupt the scheme, if it were turned down, another lengthy appeal and inquiry would follow.