JOHANNESBURG (Reuters) - South Africa's Telkom reported 24.1% growth in core profit in the first quarter, buoyed by strong subscriber growth and increased use of its "next-generation network" (NGN) offerings as it ditched legacy services.

Core earnings or EBITDA at South Africa's third-largest telecom company grew to 2.8 billion rand ($151 million) in the three months ended June 30, the operator, majority-owned by the government, said in a statement.

Overall group revenue rose 3.9% to 10.9 billion rand, driven by high demand for NGN services, including fibre and 5G, which now account for 80.7% of group revenue, Group Chief Executive Serame Taukobong said.

"NGN broadband offerings, enabled by our ongoing capital investment in our mobile and fibre networks, have positioned Telkom advantageously as the best-value mobile network," Taukobong said.

He added that the group's strategy for its fibre optic network "further improved the market-leading home connection rate to 49% for the quarter."

The group's NGN revenue grew by 7% to 576 million rand, with key contributors being mobile service revenue growth of 9.5%, fixed data growth of 7.1% and information technology growth of 10.3%.

Telkom's mobile subscribers grew by 14.6%, surpassing the 21 million mark, while homes connected with fibre grew by 19.5% year compared with a year before, it said.

On selling its mast and towers business Swiftnet for 6.75 billion rand, Telkom said the Competition Commission recommended that the proposed transaction be approved with conditions.

Telkom recently raised funds by means of a public bond auction and successfully issued two bond instruments with three-year and five-year tenors, raising 345 million rand and 405 million rand respectively, it said.

The money will refinance maturing debt and address upcoming maturities in its 2025 financial year.

($1 = 18.4928 rand)

(Reporting by Sfundo Parakozov; Editing by David Holmes)