Sydney's best-known restaurant, Icebergs Dining Room and Bar, will reopen Wednesday, marking its 20-year anniversary with a rebirth after an eight-month renovation that was supposed to take only four.

The rebuild of the restaurant, which sits above the Bondi Icebergs ocean pool overlooking North Bondi and the Pacific Ocean, was "riddled with problems", including extensive corrosion, sickness and delivery delays, says restaurateur Maurice Terzini.

The renovation began in May and was scheduled to be completed in September.

"I've done 30 [restaurant] openings so it's not like it's my first rodeo. We were riddled with problems back in 2002 and we're riddled with problems now. It's a complex site, it's crown land," Terzini says.

Yet despite the team's hard work (Terzini says he's been working 21-hour days in the lead up to the reopening), the restaurateur insists it remains essentially the same restaurant that garnered international attention from the likes of celebrity chef Nigella Lawson, who famously declared Icebergs was her "favourite restaurant in the whole world".

"We've worked extremely hard to maintain the DNA of Icebergs," he says. "Icebergs wasn't broken. We just renovated what needed to be renovated." The opening will be the most high-profile of summer in Australia.

Many of the changes in the restaurant are practical: a larger kitchen with sustainable induction cooktops; a new temperature-controlled wine cellar closer to the dining room; and hidden waiter stations.

Others are cosmetic, designed to make the restaurant feel "lighter, fresher and more Bondi". The tables are topped with teal-glazed terracotta tiles, reflecting the views of ocean and sky, and the rusted-through chandeliers have gone, replaced by "graphic, architectural" high-tech lighting from Milan.

"It's an entirely new nocturnal landscape," says Terzini.

He has partnered with Rome-based designers Carl Pickering and Claudio Lazzarini of Lazzarini Pickering Architetti to revamp the space with a familiar colour palette, layout and sense of occasion.

Pickering and Lazzarini first put their stamp on Icebergs in 2002, when Terzini hired them to realise his $3 million vision of a world-class restaurant in a relaxed oceanside suburb.

This time around, after "years and years of trying to get the development application approved", the terrace has been enclosed to allow for all-weather service and the occasional private dining event.

"It looks out onto the ocean, over the horizon, rather than the beach and the buildings," Terzini says. "It's spectacular."

The new menu by head chef Alex Prichard plays to Iceberg's strengths with an emphasis on "Japanese-inspired, Italian-driven" seafood dishes such as grilled cuttlefish with agrodolce and treviso; koshihikari risotto with XO sauce and scarlet prawn crudo; and blue-eye trevalla with oregano butter and garlic chives.

Terzini says he's most excited about the seafood crudo platter, "a nod to our old DNA". A massive seafood trough installed in the dining room will showcase a daily rotation of fresh-caught whole fish, prawns and yabbies.

"We're fortunate to work with so many great fishmongers and we wanted to showcase their wonderful work," Terzini says.

"But we didn't want it to look like a retail store, so it will just be about what product we're loving that day."

The restaurant's reopening will coincide with the release of its first book: Icebergs Dining Room and Bar 2002-2022. Part retrospective, part cookbook, the book will feature recipes from past chefs Karen Martini, Orazio D'Elia and Paul Wilson.