Vox Telecom aims to provide faster internet speeds and competitive data prices as it embarks on a R550m capital investment.
The bulk of the money will go towards its fibre-optic network project.
The increasing availability of fixed-line fibre network infrastructure has stimulated the take-up of data services, including video streaming.
On Wednesday, the telecommunications company said that in addition to Cape Town, Pretoria and Johannesburg, it would target businesses and homes in areas such as Pietermaritzburg, Bloemfontein and Richards Bay.
CEO Jacques du Toit said the company would deploy its own fibre in some areas and lease capacity from other companies that already had similar infrastructure in other areas.
"We won’t be targeting areas prone to duplication. We have identified the right type of customers and locations," he said.
Du Toit said Vox had secured 86,000 fibre-to-the-home and more than 10,000 fibre-to-the-business opportunities.
He said Vox would lease capacity to other companies in areas where it deployed its fibre network.
Vox also planned to increase its sales force from 280 to 450 people in the next 18 months.
Du Toit said the company would have "the largest direct sales force in the South African telecommunications sector and will continue to take market share from the incumbents".
It would also recruit resellers for its products, said Du Toit.
He said the R550m capital investment demonstrated that Vox’s shareholders believed in what the company was doing and "also shows that investing in fibre is the right thing to do".