Aproximately 100 employees in three firms will have to move out of their offices when they are converted into flats.
Reigate and Banstead Borough Council (RBBC) has received a Notification of change of use to reclassify Consort House, in Consort Way, Horley, from offices into 32 homes.
The Department for Communities and Local Government (DCLG) has allowed such a change of use as Permitted Development, meaning no planning permission is needed.
However, the office block is occupied by three firms with about 100 employees.
Horley Town Council planning chairman Cllr Mike George thought this went against the spirit of the legislation.
He said: “DCLG change was surely meant for unoccupied or under-used buildings and not for thriving businesses in a town centre undergoing regeneration initiatives.“
Cllr George has written to Horley MP Sam Gyimah to ask him to put forward a bill to amend the legislation so that only under used or vacant office blocks can be turned into flats before this happens in other areas.
He said: “Every office block not owned by the company could be converted by the owner of the building, for residential use.
“It has the affect of driving businesses and jobs away from the town centre.”
The change of use will go ahead by 2016.
Companies currently occupying the block include Haines Watts.
John Pannett, director at Haines Watts, said he expected he and his employees wouldhave to move from the office block when the lease ends next year.
He said: “We’ve been in Horley 32 years. We can’t say for sure yet but we are having to look at premises in other areas as a possibility because we don’t know that there will be any available in Horley
“This is a problem all over the country but for Horley it is a real blow. Here we are, we’ve got a new Morrisons in the town centre and now the workers who would usually use it may not be in the town any more.”