Forest & Bird reports the group of tourists and locals were standing near Marine Parade where the little blue penguin (kororā) was fatally hit.
The penguin was breeding age and its mate was seen calling for it for over an hour after it was killed.
Forest & Bird do not know if the pair had eggs, however, they said it was likely to be the case as it is the current breeding season for little penguins.
A member of Forest & Bird's South Canterbury branch committee, Kimberley Collins, said it is time for a change on Marine Parade.
"We have long been aware of people driving at excess speeds along Marine Parade," Collins said.
"We often take down the registration numbers of vehicles that we see speeding and report them to local police.
"Yet people continue to speed past — sometimes at up to 100 km/h."
Little blue penguins are protected and under The Wildlife Act 1953, the maximum penalty for killing protected wildlife is a $100,000 fine and up to a year in jail.
Forest & Bird South Canterbury have contacted Timaru District councillors and have launched a petition online to reduce the speed limit in the area.
Collins said it was important for a change to be made by the Timaru District Council due to the increased number of people in the area over summer.
"This is a safety issue - for the penguins that call Caroline Bay home, but also for the people who come to watch them come ashore," she said.
"In the last week alone, we have seen between 50 and 100 visitors each night, and those numbers will only rise in the coming summer months."
