Uzbek voters have reportedly approved a package of constitutional amendments in a referendum, creating the possibility of the incumbent president staying in power until 2040.

Local media outlets reported on Monday that more than 90 percent of the voters backed the proposed amendments in Sunday's referendum.

The reforms include extending the presidential term to seven years from five. Also, the president who is in office when the constitution is revised will be exempt from the rule banning more than two successive presidential terms.

Together, these mean that President Shavkat Mirziyoyev, who took office in 2016, will be able, in theory, to remain in charge of the country until 2040.

Mirziyoyev has pursued economic deregulation and other reforms, abandoning the hardline approach his predecessor took following the country's independence from the former Soviet Union.

The opposition raised concerns about the amendments, saying more power could be concentrated in Mirziyoyev's hands.