Bromley Council plans to shut Waldo Road recycling centre for more than a year from February 2, 2025, and has advised people to use Churchfields Road tip instead.
The £11 million project will see the waste transfer station at the site upgraded with a new roof and cladding.
But councillor Will Rowlands has now confirmed that it is “unlikely” Churchfields Road will be open as usual for traders to use while upgrade works to Waldo Road take place.
Instead, only residents disposing of non-commercial waste will be able to use the site through a new booking system.
Landscape gardener Rod Reed has said it seems “incredible” that businesses will be banned.
“I’ve gone to Churchfields for years, I have run my business for 40 years and we have never had a situation like this,” he added.
“Bromley is London’s biggest borough by geography, and this will affect thousands of businesses.”
Cllr Rowlands said there were “alternative commercial sites available nearby” for any traders who are impacted by the changes.
But Mr Reed said that the nearest other sites to him are “half-a-day’s drive away”.
“You can imagine the amount of fly-tipping that could result from this could be horrendous, people are going to be frustrated,” he added.
“Churchfields is a vast site, and it shouldn’t be beyond the wit of anybody to get a good trade channel going through there.
“What’s absolutely incredible is that we’re in the middle of a financial crisis and the council’s basically going to lose a lot of money from this.”
Cllr Rowlands said that the council had announced the closure at Waldo Road “as early as possible” to try and minimise disruption.
He added: “As a trader myself, I completely understand the problems this will cause and we are implementing measures to minimise inconvenience to residents and traders alike.
“Whilst we cannot say for certain that this site will not be open to traders, at this moment it looks unlikely.
“We are expanding our weekend garden waste collection scheme, with these sites open from spring next year for the entire gardening season, with additional capacity also being brought to help with bulky waste collections.”