By Raushan Nurshayeva and Mariya Gordeyeva
ASTANA/ALMATY (Reuters) - Kazakhstan's President Nursultan Nazarbayev on Friday appointed his daughter Dariga as a deputy prime minister, rekindling speculation about who might replace him at the helm of Central Asia's largest economy.
Nazarbayev, a 75-year-old former steelworker, has ruled the vast steppe nation of 17.5 million since 1989, tolerating little dissent. He has said he will personally groom a successor but not hinted who it might be.
The issue of the succession is closely watched by foreign investors who have put more than $200 billion into Kazakhstan, the second-largest post-Soviet oil producer after Russia.
Dariga Nazarbayeva, 52, replaces Deputy Prime Minister Berdybek Saparbayev, responsible for social policy. Before her appointment, she was deputy speaker of the lower house of parliament and led the faction of her father's ruling party.
"Of course, such a personnel changes in Nazarbayev's close circle should be viewed as preparations for a transit of power," Kazakh political analyst Dosym Satpayev told Reuters. "For her (Dariga) this is a serious promotion."
Kazakhs are grumbling about falling living standards after a plunge in the tenge currency and hikes in petrol prices which are likely to spur inflation. The economy grew by 4.3 percent in 2014 but is officially forecast to decelerate to 1.5 percent this year.
Nazarbayev, who has overseen fast market reforms and is highly popular despite crackdowns on dissent, has told his countrymen they will have to tighten belts and learn to live with oil prices at $30-40 per barrel, with some large-scale social projects to be cancelled.
"This job in charge of the social sector is not a piece of chocolate, to put it mildly," Satpayev said. "But beyond all doubt, she will need this experience in the future."
The country's small and disparate opposition was highly critical of the appointment, which came on the day Nazarbayev oversaw lavish festivities to celebrate the 550th anniversary of the Kazakh Khanate.
"There are clear dynastic overtones behind this appointment," opposition activist Amirzhan Kosanov told Reuters. But he added that Nazarbayev's successor could turn out to be a completely unknown face.
"Taking into account this complete state monopoly of mass media, a new president can be 'moulded' in just three months if need be," he said.