Brazilian President Jair Bolsonaro makes a heart's shape with his hands to supporters outside Alvorada Palace in Brasilia on Wednesday. Photo: AFP

Brazilian President Jair Bolsonaro was rushed to hospital early Monday with abdominal pain that doctors found was caused by a partial intestinal blockage, and is facing potential surgery nine months out from elections.

Bolsonaro, 66, was on vacation at the beach in the southern state of Santa Catarina when the pain started, his latest health problem since being stabbed in the abdomen during the 2018 presidential campaign that brought him to power.

The far-right leader was rushed to Sao Paulo on the presidential plane. Brazilian channel TV Globo carried images of him walking unassisted as he disembarked with his entourage, and the president's office said he was "doing well."

Bolsonaro posted a picture of himself in his hospital bed on Twitter, flashing the thumbs-up sign, with a message saying he was facing "possible surgery for an internal blockage in the abdominal region."

"I started feeling unwell after lunch Sunday. I arrived at the hospital at 3 am today," he tweeted after being admitted to the Vila Nova Star hospital.

"They gave me a nasogastric tube," a device to carry food and medicine to the stomach through the nose.

"They'll be doing more exams to decide if I need surgery," he added.

Bolsonaro has undergone at least four surgeries stemming from the knife attack that nearly killed him, perpetrated by a man who claimed he was following God's orders, and who was later ruled mentally unfit to stand trial.

Bolsonaro's medical team said the president was suffering from an "intestinal subocclusion," a partial blockage of the intestinal tract.

"He is stable, undergoing treatment and will be reevaluated throughout the morning," his doctors said in a statement.

"At the moment, there is no forecast for his release."

The lead doctor, surgeon Antonio Luiz Macedo, who has operated on Bolsonaro in the past, was himself on vacation in the Bahamas.

He rushed back to Brazil on a charter plane sent by the hospital, telling newspaper Valor he would only decide whether to operate after arriving late in the night.

"I'm his surgeon, and I'm the one who will decide. I need to do a clinical examination first," he said.

Bolsonaro was last hospitalized in July for an intestinal obstruction that gave him persistent hiccups.

On that occasion, doctors opted for a "conservative treatment" course, prescribing a liquid diet and deciding not to operate.

Bolsonaro regularly tears up when speaking about the knife attack.

Despite losing 40 percent of his blood, he survived and went on to win the presidency that October, fueling supporters' die-hard faith in the man they call "Mito" - "The Myth."