The biennial, which started in 1951 and is the second oldest art biennial in the world after Venice, dating back to 1895, is scheduled to open its doors next Saturday.
But it will do so amid controversy after more than 50 artists urged organizers to return around $40,000 funding from Israel, whose consulate in the city is one of the sponsors of the event, in protest at the recent conflict in Gaza.
An artist from Ramallah, Ruanne Abou-Rahme, due to exhibit at the show with fellow Palestinian Basel Abbas, was among some 60 signatories to an open letter to organizers, prompting Globo daily Saturday to dub the event the "Biennial of conflict."
Three Israeli artists are set to feature with around 70 participants in total at this year's event. The exhibition's website shows the Israeli consulate, which could not be reached for comment Saturday, as a sponsor.
Globo, however, quoted, Consul-general Yoel Barnea as saying he was surprised at the row.
"We are democratic -- there are different points of view in our country," said Barnea, adding he did not want to see culture and politics mix. He insisted the sponsorship would not be withdrawn and that he planned to attend the show.
The letter indicated the signatories were unhappy that the event, founded in 1951, "has accepted money from the Israeli state."
The group urged the organizers to reject the funding, reported to be in the region of $40,000 for the event, overall budget some $10.5 million.
The letter did not say if the artists would boycott the event if organizers failed to return the sponsorship to Israel.
Israel's campaign in Gaza saw Brazil recall its ambassador from Tel Aviv in July in protest at civilian casualties.
Israeli foreign ministry spokesman Yigal Palmor responded by dubbing Brazil a "diplomatic dwarf," forcing Israeli President Reuven Rivlin to apologize to Brazilian counterpart Dilma Rousseff earlier this month.
Aside from Israel, a number of other governments are supporting the Biennial, including Britain, France, Germany and Mexico.