A hospital spokesperson said the man was taken to the emergency department to be assessed and was admitted yesterday in a stable condition. He later died.
Four fire trucks and the Hazmat unit were called to the hospital.
Tauranga Fire Service senior station officer Phil Price said paraquat could have devastating effects.
"It's quite nasty stuff. If people ingest any significant quantity of it, it's generally fatal," he said.
Mr Price said firefighters initially set up for a quick emergency decontamination but when the ambulance arrived and it appeared the patient could wait a few minutes the full tent was erected.
He said the patient and ambulance staff were showered with warm soapy water and stripped of their clothing before being admitted into the hospital.
All their clothing was bagged and tagged and would be laundered and returned to them or destroyed.
National Poisons Centre toxicologist Leo Schep said paraquat was extremely toxic when ingested.
He said the poison was hazardous when it came into contact with cuts or broken skin.
Mr Schep said the product would kill plants but lost its toxicity when it came into contact with soil and this could be used to help treat people who had been poisoned by paraquat.
"Get some soil, put it in water, shake it up and drink it," he said. He said ambulances used to carry Fuller's earth, clay-like material, for use in such situations.