Harare, Zimbabwe (CNN) -- Zimbabweans voted Saturday for a key referendum on a new constitution that limits presidential terms for the first time in the African nation.
Robert Mugabe, 89, has been in power for decades, first serving as prime minister in 1980 and taking over as president seven years later.
"This is a Zimbabwean document to replace a British one. That is why I voted for it," said Babra Mheno, 34, a university student, referring to the nation's former colonial rulers.
If approved, which is highly likely, the constitution will give more powers to the parliament and limit the president's. It also introduces a two-term limit of five years each for a president.
The limit will not apply in retrospect, which means Mugabe has 10 more years as head of state if he is re-elected.
"I have voted no for the document," said Kizito Marwe, at a polling station east of Harare. "It was written by politicians, not Zimbabweans."
The 27-year-old said he'll spend the rest of the day taking advantage of the public holiday.
"I was in line for two hours. I am heading home and spending the day watching TV," he said.
Mugabe has indicated he will run for re-election during the polls scheduled for between July and October.
The referendum -- one of the conditions set before an election -- clears the way for the first poll since a disputed outcome plunged the nation into chaos in 2008.
The upcoming election will end the fragile coalition between Mugabe and Prime Minister Morgan Tsvangirai.
Both entered a power-sharing agreement in 2009 after regional leaders nullified Mugabe's victory,citing violence by his loyalists targeted at rival supporters. The two leaders are expected to run for president.
About half of the nation of 12 million is expected to vote in the referendum.
The referendum also addresses gender equality, and sets aside 60 parliamentary seats for women out of a total of 310.
In days leading up to the referendum, Mugabe shut out Western observers, but allowed monitors from African nations to take part.
Sporadic reports of violence have marred campaigns in the days leading up to the election.
"We should not have violence ... the party will not tolerate that nonsense (political violence) whether it is intra-party or inter-party," Mugabe said in a statement this week.
CNN's Nana Karikari-apau contributed to this report