Miss Ewart said the signs worked for her and other businesses, and they warned people to slow down if they wanted to stop.
"Coming into Wairarapa, how else are small businesses, and large businesses, going to let people know what we have to offer?
"I'll be out of business if the signs go down. It's very important for trade."
Miss Ewart said there could be a better plan which a group of sign owners were hoping to discuss with council.
"If it's a safety issue spread them out."
The rules include limits on size, the number of words and material used, which was "really nit-picky", she said.
White Swan owner Rob Slater, whose sign has been up for more than four years, said it was "madness" and there could have been a better way for council to go about it.
"I think it's absolutely crazy, I just don't understand the rationale behind it. There's been no consultation."
He said the signs helped give people reasons to stop in Greytown.
"It's all part of promoting your business, if they don't know there's a nice place for a coffee, a supermarket or somewhere to stay the night ... they'll keep on driving."
FreshChoice supermarket owner Chris Ward said he put up a sign 12 months ago and had contacted the council but did not get resource consent.
Because there were signs everywhere, he decided to put it up anyway.
"NZTA said 'we won't give you approval'."
He said there could be a limit on signs per kilometre instead and owners could be accountable for maintaining signs.
"I have a bit of difficulty with the answer just being no. [But] If the legislation says the signs are illegal then we'll have to take them down."
Bayleys Wairarapa manager Mark Morison said the signs had been up for many years and they would comply as long as it was consistently enforced.
"If one is singled out that's not fair."
Council group manager planning and environment Murray Buchanan admitted they had not been checking whether signs were complying and would now regularly check them.
"It's gotten away on us a little bit."
He said competing businesses began pointing the finger once the council realised there were a lot of illegal signs.
"When we started enforcing it, people said what about all the other signs? We felt it was a bit unfair to pick on one business, if we are going to enforce it on one we need to do it for all."
Different rules apply to signs which don't advertise businesses, such as tourist information signs.
Mr Buchanan said the on-site activity rule was to stop signs from spreading all over the countryside and it was also a safety issue.
The council has to consult with NZTA, as the owner of the highway, when resource consent for a sign is applied for.
He said the council was unlikely to grant consent because of the on-site activity rule.
NZTA generally did not like signs on the side of main highways as it was a high-speed zone and signs could distract drivers. Off-site signs can go up in commercial and industrial low-speed zones. "There would be potential sites further up the road to alert people."
