The constitutional amendments included changing Article 140 to allow Egypt's President Abdel Fattah el Sisi to extend his current four-year term, which ends in 2022. A second change also permits Sisi to stand for another six-year term.
Egypt's parliament, packed with loyalists of President Abdel Fattah el Sisi, voted on Tuesday on a package of changes to the constitution that could keep the former military chief in power until 2030.
The amendments were initially introduced in February by a parliamentary bloc supportive of Sisi and updated this week after several rounds of parliamentary debates.
They include changing Article 140 of the constitution to allow the Egyptian president to extend his current four-year term, which ends in 2022, by two years.
A further amendment would permit Sisi to stand for another six-year term and potentially remain president until 2030.
The vote sends the amendments to a national referendum which is now likely to take place before early May when the Muslim holy month of Ramadan starts.
Sisi led the army's overthrow of elected president Mohamed Morsi in 2013 following protests against the latter's rule.
Sisi won his first term as president in 2014 and was re-elected in March 2018 with more than 97 percent of the vote, after standing virtually unopposed in the wake of the decimation of much of the organised opposition to the coup that brought him to power.
His government has been widely criticised by human rights groups for the repression of political opponents.
Pro-Sisi legislator Mohamed Abu Hamed, a proponent of the constitutional amendments to keep Sisi in power, is adamant that the changes are a must.
"The constitution in 2014 was written under tough exceptional circumstances," he said.
He hailed Sisi as a president who "took important political, economic and security measures ... [and] must continue with his reforms," in the face of the unrest gripping neighbouring countries following the toppling of veteran president Omar al Bashir in Sudan and the escalation of the conflict in Libya.
Keeping Sisi in power, he added, reflects "the will of the people."
Since Sisi overthrew Morsi, Egypt has drawn heavy international criticism for its sweeping crackdown on dissent.
The authorities have jailed thousands of Morsi's supporters as well as liberal and secular activists, including a popular blogger, actors, singers and journalists.
Last week, Human Rights Watch (HRW) warned that the amendments, which would also increase the military's political role and grant Sisi control over the judiciary, would "institutionalise authoritarianism."
As Sisi visited Washington for talks with President Donald Trump, HRW urged Congress to withhold endorsement of the Egyptian president's bid to extend his rule.
"Congress needs to use its levers to pressure the Egyptian president to reverse course, starting with withdrawing these constitutional amendments set to consolidate authoritarian rule," said HRW's Michael Page.
As well as a crackdown on dissent, Sisi has overseen a military campaign against Daesh-linked militants based in the Sinai Peninsula.
The 596-seat parliament was also to vote on a controversial article which critics fear might allow the military a greater influence in Egyptian political life.
Other proposed amendments include a quota for women's representation of no less than 25 percent in parliament and forming a second parliamentary chamber.