American burger chain In-N-Out has taken a Sydney rival to court to stop it using the name Down N' Out, claiming the local business is trying to "mimic" its offerings and is misleading consumers.

The California-based In-N-Out Burgers Inc launched Federal Court proceedings in October last year against Hashtag Burgers, which is headquartered in Coogee and operates Down N' Out restaurants in the Sydney CBD and Ryde in the north-west.

Down N' Out restaurant in George Street, Sydney, is at the centre of a Federal Court dispute with the US burger chain In-N-Out. Credit:Janie Barrett

The legal bun fight may take more than a year to be resolved, with a court date pencilled in for June next year.

In-N-Out is seeking court declarations that Hashtag Burgers infringed its trademark and engaged in misleading or deceptive conduct by using the Down N' Out name and logo to market American-style burgers in Sydney.