Kyrgyz presidents will now be able to run for office for a second time, reversing the single-term limit imposed on leaders during an overhaul of the basic law in 2010.
Voters in Kyrgyzstan have granted sweeping powers to President Sadyr Japarov in a constitutional referendum that will also allow him to run for re-election, according to preliminary results.
Japarov, a 52-year-old populist, has brushed aside political opponents since coming to power on the back of a political crisis last October in the poor Central Asian country.
A disputed parliamentary vote saw Japarov's predecessor, Sooronbay Jeenbekov, become the third Kyrgyz president to resign during a political crisis since the country's independence from the Soviet Union in 1991 as Japarov won backing to lead from the political elite.
His release from jail by supporters was the spark for a dizzying rise to the leadership. He always described his conviction for hostage-taking – which has since been overturned – as politically motivated.
On Sunday, with nearly all ballots counted, the constitutional changes were on course to pass with 79 percent in favour.
Turnout was low but at nearly 37 percent crossed the 30 percent barrier required for the referendum's results to stand, the Central Election Commission said.
Japarov had already confirmed his dominance over domestic politics in January, when he won the presidency in a landslide.
The president had appealed to voters to back the constitutional changes, claiming that previous revisions had been imported from abroad.
"This time we prepared the basic law ourselves," Japarov said as he cast his ballot at a polling station in the capital Bishkek.
The result promises a presidency more in line with Kyrgyzstan's neighbours, with the office gaining new powers of appointment at the expense of parliament and the head of cabinet, ending a decade-long experiment with a mixed system.
Adis Asanov, a 65-year-old pensioner, told an AFP correspondent in Bishkek that he had voted for the new constitution because of his disappointment with parliament's lawmakers who had "bought their seats and lobbied their own corrupt interests".
"Japarov's government promises to work for the people. I personally believe him," Asanov said.
Local critics dubbed the hastily drafted document a "khanstitution", evoking the powerful patriarchs who ruled Central Asia in centuries gone by.
Anara Nasyrova, 61, told AFP that she had voted no in the referendum and did not trust Japarov.
"What happened to his promises to fight corruption? We see only the usual raiding," she said. "He doesn't have the teeth or the brains for reforms."
The Organisation for Security and Cooperation in Europe and the Council of Europe's Venice Commission criticised the lack of "meaningful and inclusive public consultations and debate in parliament" before the basic law was put to the people.
In a joint opinion published in March, the two bodies also raised fears over the "overly prominent role and prerogatives of the president".
READ MORE: Tackling kleptocracy in post-Soviet states
President Vladimir Putin of Russia, a key ally, expressed support for the constitutional drive in February when Japarov went to Moscow in his first foreign visit, saying that he hoped it would bring stability to the country of 6.5 million.
As a result of the referendum, Kyrgyz presidents including Japarov will be able to run for office for a second time, reversing the single-term limit imposed on leaders during an overhaul of the basic law in 2010.
That change was championed as a safeguard against entrenchment after two revolutions in the space of five years unseated authoritarian leaders and their powerful families.