SALES of fast food giant KFC in China slumped an estimated 36 percent last month, according to parent Yum! Brands, as consumers shunned chicken due to the H7N9 bird flu outbreak in humans.

For Yum overall, which includes other restaurant chains such as Pizza Hut, Chinese same-store sales - a measure of turnover in established outlets - fell an estimated 29 percent in April.

"Beginning the first week of April, publicity surrounding avian flu in China has had a significant, negative impact on KFC sales," Yum said.

China is a key market for Yum, which has more than 4,200 KFC outlets here.

"Historically, the impact of this publicity has initially been dramatic at KFC but relatively short-lived," Yum said.

"As in the past, we are reminding consumers that properly cooked chicken is perfectly safe to eat."

But Yum recorded a 20 percent year-on-year fall in its China sales in the first quarter, a previous statement said, after authorities found excessive levels of antibiotics in chicken KFC sourced from local suppliers.

KFC said it had taken measures to ensure food safety and win back trust from customers.