The public's chance to have their say on a proposed extension to London's congestion charge zone ends on Friday.
Two thirds of affected Londoners currently oppose the expansion
Mayor Ken Livingstone wants to extend the congestion charge boundary into Kensington and Chelsea.
Conservatives in the London Assembly said the mayor, who raised the charge from £5 to £8 last week, must listen to people's concerns.
The first round of consultations last year found two-thirds of those affected opposed the scheme.
Conservative Congestion Charging spokesman Angie Bray said: "Will Ken Livingstone ignore us if he gets another massive thumbs down?
"In the first consultation 66% said no, and he ignored it. This time, with the charge now at £8, the no could be even higher. How can he justify continuing to ignore Londoners in such a cavalier way?"
New figures reveal 85% of businesses believe the mayor will implement the western extension irrespective of the findings of Transport for London's 10-week public consultation.
The figures come from a survey of 140 businesses by the London Chamber of Commerce.
If the congestion charge extension gets the go-ahead it could be in place in west London by late 2006.