A wildlife scientist says people relieving themselves on top of Uluru may have killed off a rare species of shrimp.

Retired university professor Brian Timms says he has studied museum specimens of small inland shrimp that live in pools on top of Uluru.

He says his research shows the localised extinction of one species of fairy shrimp and the dominance of another - changes which could be due to human waste.

"It's happened already that the people going up the rock somehow have affected the animals which live in the pools, possibly by peeing on the rock and pooing on the rock," he said.

He says the Branchinella Latzi shrimp species, which once inhabited rock pools on Uluru, has not been found in collections since about the 1970s.

"Latzi is a very limited species and it might be susceptible to enrichment of the pools whereas [the other species on Uluru] is a widespread, tough species," he said.

"Certainly if they [tourists] go up, they should be behaving themselves, not pooing on the rock."

Earlier this month an Uluru tour guide told the ABC that tourists climbing the rock are sometimes defecating at the top because there are no toilets available.

The Director of National Parks continues to assess submissions on a draft management plan for the Uluru-Kata Tjuta National Park, which proposes banning climbers from the rock for cultural, safety and environmental reasons.