Ms Dean, who has volunteered for six summers at Sandfly Bay, said she approached the German tourist when she saw smoke billowing up from the dunes where the public were asked not to go.
"I shot up the dunes, yelling for him to put it out. He had his tent up and a sturdy fire going under the shelter of marram grass.''
She kicked sand on the fire and dragged the main log down the beach to the water.
The tourist, who had walked to the beach, was urged to leave.
DoC biodiversity programme manager Dave Agnew said it was another stress those working with the yellow-eyed penguins did not need after having to rescue underweight chicks and pick up their dead parents.
Tests at the Cawthron Institute to see if a marine biotoxin had caused the penguin deaths had come back negative, so environmental testing, including deep water testing in known foraging sites, would take place next week.
On the positive side, no dead penguins had been found in the last three days, he said.
Volunteers, DoC staff, the Yellow-eyed Penguin Trust and tour operators would continue to scour the beaches during the next week.