New opening: Jazz City Milk Bar

US-style diners have been popping up across Sydney in recent years, now American chef Dan McGuirt is having a bet on the diner, ice-cream parlour and the local milk bar being the next big things.

On Thursday he opened Jazz City Milk Bar in the courtyard at Republic 2, home to Universal restaurant.

''I travelled around here and the States looking at them for the design,'' McGuirt says.

There's also a touch of yesteryear to the menu, which includes root-beer floats, milk and cookies, and Eggs Louis Armstrong.

The dinner menu has more of a 21st-century flavour, with oatmeal-mushroom risotto, rabbit served three ways and a ''Killer Diller'' Cajun meatloaf with buttermilk-mashed potatoes.