Officials in the Caucasus country say lengthening the president's term from five to seven years was backed by a 'vast majority' of voters.
Azerbaijan has voted in a referendum in favour of extending the president’s term in office from five to seven years, according to election authorities.
Critics say President Aliyev will get unprecedented powers. He can already seek re-election indefinitely after a maximum number of terms in office was scrapped via a similar referendum seven years ago.
The state election commission said a vast majority of the 91 percent of voters who turned out in the Caucasus country had backed the longer presidential term.
The authorities argue it will ensure continuity in decision-making, which they say is vital after a slump in oil prices hurt the country’s economy.
There was also strong support for constitutional amendments giving the leader the right to call early presidential elections at his convenience and dissolve parliament.
Before the vote the human rights body the Council of Europe said the amendments would severely upset the balance of power by giving “unprecedented” powers to the president.
European observers from the Parliamentary Assembly of the Council of Europe (PACE) recognised the results but called on the Azeri authorities to improve the voting process.
European democracy watchdogs have said previous votes in the ex-Soviet country were marred by vote-rigging and unequal access to the media. The Baku government denies the charges.