Zambia's largest mobile phone operator Airtel is to spend over $80 million on upgrading and expanding its base station infrastructure.

The company said it expects to finish upgrading its sites by the end of the year in a bid to boost the quality of calls and internet on its network.

Airtel head of corporate communication Yuyo Kambikambi said 58 new 3G sites are also planned.

"So far there are 58 new 3G sites that are meant to give the fastest internet speed. We expect to finish upgrading over 242 sites by the end of this year," Kambikambi said.

Airtel customers have been complaining about the company's poor network over the past few weeks.

However, Airtel said that the poor network quality is as a result of the change-over from older sites to newer ones.

The company also said it expects to have network outages during the course of the exercise.