The proposals on the ballot pushed by President Rafael Correa include an effort to rein in what he has called the "mediocre and corrupt" media structure in the South American nation.
Correa, in office since 2007, is also seeking to ban bull-fighting and gambling across the Andean nation.
Authorities have however dropped a controversial measure seeking to also ban cock-fighting.
The bull-fighting measure could be the most contentious for voters:
Ecuador is one of the foremost bullfighting sites in Latin America, hosting 400 annual events in an industry that brings in some 50 million dollars a year.
Some 30,000 jobs rely directly on the blood sport, industry officials say.
Correa is also hoping to amend the constitution to restrict investment in local media. Critics say the move is a veiled attempt to muzzle dissent.
The divestment effort is also aimed at preventing media from investing in banks, and vice versa. The 2008 constitution passed during Correa's term has already barred banks from owning media outlets.
Diego Cornejo, chief of the National Newspaper Editors' board, claims the effort would violate basic business rights.
If there were a wave of media sell-offs with banks unable to take part, many smaller media outlets could end up in state hands, with state control over editorial content, he said.
"We are not defending the right of bankers to own media, rather we are defending freedom of thought and the right not to be censored," said Marcel Rivas of the local television channels' association (ACTVE).
The referendum also seeks a media law that would set up a council to regulate violent, sexually explicit and potentially discriminatory content.
Media workers have expressed outrage at the move because it would hold individual journalists criminally responsible for such violations.
Correa, who has torn up newspapers at public events and tarred some columnists as "ink-stained hitmen," has argued: "There is no freedom without responsibility. And these guys want total, unfettered power."
In March Correa filed multimillion-dollar libel suits against three newspaper executives and three journalists in what has become an escalating war with the media in recent months.
Editors and journalists insist those cases, like the proposed media laws, are a clear attempt to stifle free speech.
Foreign Minister Ricardo Patino denied the allegations, telling AFP:
"This government has decided to lead, and some media do not support that."
"We only defend ourselves," he added, insisting that in Ecuador there were "no journalists in prison."
The referendum includes another proposal by which Correa hopes to revamp what he sees as a "corrupt" and "ineffective" judiciary.
Former interior minister Gustavo Larrea, a Correa critic, has slammed the proposal, calling it "an authoritarian project" and an attempt to "control the courts."
The Ecuadoran polling group Investigations and Consult Marketing Solutions said more than 66 percent of voters are expected to approve the proposals, with around 33 percent rejecting them.
Correa, an ally of leftist Venezuelan President Hugo Chavez, was re-elected in 2009 as leader of the largely poor yet resource-rich South American country of 14.5 million.
In a country with a long history of political instability, three of Correa's predecessors from 1996 to 2006 were ousted before completing their terms.