(Adds quotes, updates turnout with polls closed)
ASHGABAT, Feb 12 (Reuters) - Turkmen President Kurbanguly Berdymukhamedov is certain to secure a third term in Sunday's election, maintaining his grip on power in the gas-rich nation which he wants to take into the ranks of the developed world.
Berdymukhamedov, 59, has run the former Soviet republic of five million people with an iron fist for a decade after succeeding equally autocratic president-for-life Saparmurat Niyazov who died in 2006.
Berdymukhamedov, a dentist by training, has kept in place Niyazov's repressive political system which tolerates no political opposition or public expressions of discontent, while refocusing his predecessor's elaborate personality cult on himself.
While Niyazov was known as Turkmenbashi, the head of all Turkmen, Berdymukhamedov is often referred to as Arkadag, the protector. Gilded statues of both leaders have been erected in Ashgabat, the capital city.
Berdymukhamedov cast his ballot at a downtown polling station after arriving with his family, including his son Serdar who last year became a member of parliament after winning a by-election.
"Turkmenistan's goal is joining the ranks of the industrially developed nations," Berdymukhamedov told reporters, adding that all candidates had had equal opportunities in the election campaign.
Running against Berdymukhamedov are eight other candidates, all of them public servants, managers of state-owned companies or nominees of political parties completely loyal to the government. In the previous election in 2012, Berdymukhamedov won 97 percent of the vote.
According to the Central Election Commission, 97.27 percent of the country's 3.2 million voters had cast their ballots by 7 p.m. (1400 GMT), when polls closed.
"He is carrying out a successful campaign against drug abuse and has promise to provide free housing for the disabled," said Zukhra, a 42-year-old medical worker who supported Berdymukhamedov.
Dovlet, 32, a taxi driver, declined to say who he had voted for, saying:
"This is my personal business and it will hardly affect election results, because all the other candidates (running against Berdymukhamedov) are little known."
Last year, Turkmenistan amended its constitution in a way that could allow Berdymukhamedov to stay in power indefinitely, removing the 70-year age limit for presidential candidates and extending the presidential term to seven years from five.
This consolidation of power has been taking place against a background of slowing economic growth and shortages of foreign currency due to Russia's decision to halt imports of Turkmen gas, Ashgabat's main source of export revenue.