For years, one-hatted eatery Three Blue Ducks rejected the relentless stream of offers from food delivery services that were desperate to partner up.

But co-chef Darren Robertson's scepticism melted away when he found out his friend Dave Pynt, head chef of Asia's 14th best restaurant, Burnt Ends, was taking part in home delivery via UberEATS.

"I'm pretty old-school and had a lot of scepticism about home deliveries, but to know someone at his level was doing it changed things for me," he said.

"We're lucky in that the sort of style of food we do lends itself to this, like it's hearty, honest, and robust and it isn't too technical."

Three Blue Ducks is among more than 100 restaurants that are part of food delivery app UberEATS, launched in Sydney on Tuesday by ride-hailing service Uber.

The app was first made available in Melbourne in April.

At present, food will only be delivered to inner Sydney suburbs - "From Bondi to Surry Hills, Pyrmont to Newtown, and everywhere in between."

UberEATS has nabbed contracts with other first-time, "premium casual" restaurants, including Sake in the Rocks and Fratelli Fresh across Sydney.

It's the latest service to appear in the booming food delivery market in Sydney, already crowded with the likes of Menulog, Deliveroo, Foodora and Suppertime.

"It's a good time to be a customer and I think there will be a lot of further growth in this sector," said David Rohrsheim, Uber's Australia and New Zealand general manager.

"We've got a range of restaurants partnering with us, including at least seven that are totally new to the on-demand delivery game."

Users can try UberEATS for free, but eventually the $5 flat fee, as seen in Melbourne, will be applied.

Sydney is the sixth city outside of the US to get UberEATS, following recent launches in London and Singapore.

Mr Rohrsheim said meals would typically be delivered in half an hour, "but shorter for cupcakes, obviously".

He said they will see how the launch goes, before expanding the service to the rest of Sydney.

He said some Melbourne eateries had increased sales by 20-25 per cent since joining the app.

Tom Pash, chief executive of Urban Purveyor Group, which owns Sake and the Fratelli Fresh chain, said it was the first time food from its "premium casual" restaurants - except Bavarian Bier Café that's partnered with Menulog - could be delivered.

"We had upwards of 10 food delivery companies wanting to work with us, but we waited and chose Uber because we wanted a premium experience that was almost as good as dining in our venues," he said.

"We surveyed our customers from Sake, Fratelli and the Cut, and found 85 per cent were already using Uber."

He said there was now potential to expand their offerings - special occasion packages for birthdays and drop-off catering for strategic accounts such as KPMG.

James Eling, founder of Marketing4Restaurants, said the entry of UberEATS was a "good thing" for the industry, as the commission was "moderate" compared with the logistics issues and costs eateries faced when attempting to deliver themselves.

"I spoke to one of our customers last week and he said that the introduction of UberEATS for their restaurant created a massive increase in the number of orders that they are getting," he said.

"UberEATS, however, is still not an option for restaurants in the suburbs or in regional towns, because they rely on the high density and availability of drivers."

Other Sydney restaurants available one the app include Butter in Surry Hills and The Thievery in Glebe.

The service is only available from 11am to 10pm.

"Our main goal is to deliver food on time and at a high quality with no disruptions along the way," said Julian Cincotta, head chef of Butter.

"It also connects us with a much larger audience while also reinforcing the prestige of our brand, because only the best local restaurants are invited."

Back at his Bronte restaurant, Three Blue Ducks' Robertson said staff, friends and family had been doing dummy runs to test a version of the app.

"We're a busy place, so we're trying to get it right and get ready," he said.

"I think we'll hit the average delivery time of 35 minutes. We've designed things so we can assemble pretty quickly," he said.

"When you make changes, people might think standards may drop so you have to try and train even harder to make sure you don't drop the ball."