The city had no immediate comment on the suit filed this week in Travis County by the Texas Retailers Association, which also contends the city does not have the authority to implement such a prohibition.
The suit said the association "has not been able to discover a single state law authorizing the banning of bags in any manner, let alone the manner adopted by the city."
The ban, which takes effect Friday, applies to thin so-called single-use bags made out of both paper and plastic. Merchants can still use plastic and paper bags made of thicker material, The Austin Statesman-American said Tuesday.
The retailers, who are not seeking an immediate injunction to block the new ban, contend merchants could lose business and find themselves stuck with unused supplies of the targeted bags. The suit also contended state law prohibits restrictions on containers for "solid waste management purposes."