The celebrity couple arrived in the morning with a small group of environmental activists.
Panettiere said she wanted to meet the mayor and representatives from the local fisheries union, but she and Jeff Pantukhoff, an anti-whaling activist from the U.S., were blocked by two officials at the door of the town hall.
"We are trying to peacefully come up with better ideas as to how to generate income and utilize the nature here," Panettiere told reporters. "We've been to Taiji before and it's a beautiful place with beautiful wildlife."
The group then moved on to the fisheries union, but it was closed. Local fishermen also refused to talk to them.
"We just wanted to have a very peaceful and relaxed conversation," Panettiere said.
Her visit to Taiji comes just weeks after "The Cove," a gory depiction of Taiji's dolphin slaughter, won the Oscar for best documentary.
Fishermen in the village on the rocky coast of southwest Japan consider the hunt a proud legacy. But it has long been targeted by hardcore environmentalists and animal lovers, and the Oscar has given the opposition more mainstream attention.
"This is going to be a tourist centre for dolphin killings," said local activist Steve Thompson, who helped organize the trip.
Panettiere, who plays an indestructible cheerleader on the hit U.S. TV series "Heroes," is also the spokeswoman for the "Save the Whales Again!" campaign, which wants to halt Taiji's dolphin hunt. The campaign cites studies that show dolphin meat contains dangerously high levels of mercury and is unsafe to eat, and says killing the animals is cruel and unnecessary.
The 20-year-old actress also protested the Taiji hunt in 2007, when along with five other surfers she paddled out into the cove where the hunt takes place in a peaceful protest that was broken up by fisherman. Scenes from that encounter are briefly shown in "The Cove."
The Japanese government allows about 19,000 dolphins to be killed each year. Taiji hunts about 2,000 dolphins every year for meat - less than other places - but is singled out in part because of its "oikomi" method of herding and killing them near the shore. Some are captured and sold to aquariums and dolphin shows at water parks.
Residents once welcomed foreign visitors, but in recent years have grown weary of what they feel are one-sided portrayals and grisly snapshots shown out of context. Overzealous protesters and photographers are occasionally approached and scolded by rough-and-tumble locals looking to defend their town's reputation.
As the group arrived, a truck of right-wing nationalists blasted slogans, saying Japan should not be singled out for whaling and dolphin hunts because Westerners "are killing cows." They also demanded President Barrack Obama apologize for the atomic bombings of Hiroshima and Nagasaki.
There were no clashes between the environmentalists and the townspeople.
Klitschko, the six-foot, five inch (196 centimetre) heavyweight boxing champion, who just last week recorded his 48th knockout in defending his WBO and IBF belts, towered over everyone as he quietly took in the day's events.
The group was due to talk to reporters on a beach in the afternoon, near the cove where the town herds dolphins to harvest them. John Quigley, an "aerial artist" who creates large works of art that can be viewed from the sky, planned to make a giant outline of a dolphin on the sand.
While Panettiere seemed likely to give the one-day protest a strong publicity boost, some questioned whether it would have any affect on persuading locals to abandon their hunt.
"The more pressure we put on them, the more they will pull back and cut us off," said Chiho McBennett, a Japanese mother who travelled with the group out of concern over the mercury issue.