Azerbaijan has held a referendum on extending the presidential term from five to seven years, a step that a European democracy watchdog said would hand unprecedented power to President Ilham Aliyev.

Aliyev, 54, succeeded his father as president in 2003 and can seek re-election indefinitely after term limits were scrapped in another referendum seven years ago.

Polling stations opened at 8am local time on Monday across Azerbaijan.

There are 5.3 million eligible voters in the oil-producing, former Soviet republic.

The authorities argue that a longer presidential term will make for more continuity in decision-making, which they describe as vital after a slump in world oil prices halted Azerbaijan‘s long run of economic growth.

“One of the main tasks of the referendum is implementation of economic reforms in the post-oil boom period in Azerbaijan, the elimination of bureaucratic mechanisms and creation of an effective governing system,” said Ali Hasanov, the president’s assistant on political issues.

European democracy watchdogs have said previous votes in Azerbaijan have been marred by vote-rigging and unequal access to the media. The Baku government denies the accusations.

The Venice Commission, an advisory unit of the Council of Europe, a rights and monitoring body of which Azerbaijan is a member, said of the referendum: “Many proposed amendments would severely upset the balance of power by giving ‘unprecedented’ powers to the president.”

Some rights activists also criticised other proposed amendments, which would give the president power to declare early presidential election at his convenience, as well as to dissolve parliament.

“The referendum has been accompanied by arrests and intimidation from the beginning,” Denis Krivosheev, Deputy Director for Europe and Central Asia at Amnesty International, said in a statement. “Those who have attempted to criticise and campaign against these proposals have faced assaults and harassment by the authorities.”

Aliyev’s rule long benefited from an economic boom fuelled by oil pumped to Europe from a region where the West and Russia are vying for influence over huge energy reserves.

But a slump in global oil prices in the past two years has weakened the Azeri currency, the manat, and shrunk the economy.

– Reuters