MTS, Russia's top mobile operator, said on Tuesday it had decided not to bid for a 51 percent stake in Kazakh provider Mobile Telecom Service.

We took into account that penetration in Kazakhstan is high, while density of population is low, and that the company has a number three market position and would need significant investments to increase its market share, MTS spokeswoman Yelena Kokhanovskaya told Reuters.

The provider was also heavily indebted and the payback period of an acquisition would not meet MTS' criteria, she said.

State-controlled fixed-line provider Kazakhtelecom said in late June it planned to sell a majority stake in its mobile operator as part of an effort to restructure its assets.

SK Telecom Co, South Korea's top mobile operator, said in July it was considering bidding for the stake in Kazakhtelecom's wireless unit.

Russia's MTS, part of services conglomerate Sistema, has more than 100 million subscribers in Russia, Ukraine, Turkmenistan, Uzbekistan, Armenia and Belarus.

(Reporting by Maria Kiselyova, Editing by Lin Noueihed)