David Riggleman, a spokesman for the city, said: "We're trying to empathise with both camps.
"We're hoping we can improve their lives and improve the lives of people living around the park, some of whom have people urinating and defecating in front of their door."
The law, which went into effect on Thursday, targets mobile soup kitchens. It carries a maximum penalty of a $1,000 fine and six months in jail.
Riggleman said that by shutting down such soup kitchens, homeless people will be encouraged to go to a centre or a charity that offers services such as mental health evaluations or job placements.
Gail Sacco, who operates a mobile soup kitchen, said the city does not have adequate homeless services and that she is undeterred by the new law.
"There's no way for people to get out to those services in triple-digit weather," she said, referring to the soaring summer temperatures in the area.
"My plan is to do anything I feel is needed to keep these people alive."
The law defines a homeless person as someone "whom a reasonable ordinary person would believe to be entitled to apply for or receive assistance".
Allen Lichtenstein, a lawyer with the American civil liberties union of Nevada, said the language makes the law unenforceable.
He said: "The ordinance is clearly unconstitutional and nonsensical.
"How are you going to know without a financial statement who's poor and who's not poor?
"It means they can discriminate based on the way people look."