Australian tourist operators on Friday called for more protection for the mammals from boats and jet-skies, following the death of dolphin calf off a Victorian beach.

Authorities said a two-month-old dolphin was found dead on the Portsea Back Beach south of Melbourn, Victoria of Australia, last week. The baby dolphin had suffered significant internal injuries, most likely caused by a boat or jet-ski.

Director of Moonraker Dolphin Swims Torie Mackinnon said she last week witnessed a "horrific" incident in which more than 20 jet-skiers were driving at a group of dolphins and their calves just off Rye, near Portsea Back Beach.

"It was the worst thing I have ever seen," she told Australia Associated Press on Friday.

"We saw children jumping off their jet-skies onto pods of dolphins trying to grab their fins as they were swimming away. Some of the dolphins we have seen are less than five days old."

Mackinnon said jet-ski traffic in southern Port Phillip Bay had doubled since last summer, which made the problem worse.

Meanwhile, Troy Muir of Polperro Dolphin Swims believes many people were ignorant about laws that stop boats from getting within 100 meters to dolphins and jet-skies 300 meters.

He said people needed to be educated about the consequences of their actions around such gentle creatures.

According to the Department of Sustainability and Environment senior compliance officer Glenn Sharp, the best way to protect dolphins was to get the message out to the public to observe them from the legal distance.

Sharp remained the public that people who ignore the laws face on-the-spot fines of 176 U.S. dollars and in more serious cases people can be criminally charged and fined more than 100,000 U.S. dollars.