The company has advised customers it will be increasing the prices of wiring maintenance and some monthly landline rental plans from June.
The price increases reflect the impact of inflation during the past year.
While landline plan prices will increase by 80c to $42.80 in Auckland, and by 75c to $39.05 in Wellington and Christchurch, the cost in all other areas (including Dunedin and Otago) will rise by 90c to $47.25.
The price of wiring maintenance in all areas will also rise by 20c to $2.99.
Otago Chamber of Commerce chief executive John Christie described the price rises as "discrimination based on region".
He questioned why "other areas" such as Dunedin and Otago had to bear a bigger price rise than Auckland, Wellington and Christchurch.
He also questioned why Otago customers had to pay $8.20 a month more than customers in Wellington and Christchurch.
"It's population driven. It's about the number of customers they've got and how secure they feel about holding them.
"It may only by 90c a month, but is that fair? It's discrimination based on region.
"Why do such variances have to exist?"
Telecom spokeswoman Emma-Kate Greer said regional pricing differences were common across providers in New Zealand for services of this type.
"This price difference reflects a number of factors associated with bringing certain services to different areas, such as population, infrastructure and competitive activity.
"These price increases reflect the impact of inflation and rising costs on our business.
"While we're trying to manage costs in other ways, we can't avoid passing on a modest increase to some basic services."
A Commerce Commission spokeswoman said there did not appear to be an issue under either the Telecommunications Act or the Commerce Act with Telecom's price increases.
Mr Christie said there was competition in the telecommunications industry and consumers had a choice. "If Telecom don't have the best price, consumers can go to other providers."
