25 Japanese tourists isolated at hospital

Twenty-five Japanese tourists have been isolated at a Sydney hospital after suffering from illness and vomiting.

"Symptoms appear to be similar to food poisoning ... it's not confirmed but they are the kind of symptoms that we are looking at," a southwestern Sydney local health district spokeswoman told AAP.

The tourists were on Tuesday isolated in part of Liverpool Hospital's emergency department and measures to control any spread of a potential infection have been put in place.

"There is no risk of any transfer to other patients," the health district said in a statement.