UPDATE 1-Supermarket firm Ahold's quarterly sales top estimates with online boost

(Adds details on results, CFO quotes)

AMSTERDAM, Feb 17 (Reuters) - Ahold Delhaize, a major operator of supermarket chains in the United States and Europe, reported better-than-expected fourth-quarter sales on Wednesday, driven by a surge in online orders during the pandemic.

In the quarter ending Dec. 31, Ahold said its sales rose 18% to 19.6 billion euros ($23.7 billion), topping the 18.5 billion euros seen in a company-compiled consensus.

Underlying operating income in the period was 811 million euros, also beating a consensus forecast of 771 million euros.

Net consumer online sales jumped 84% to 2.6 billion euros, with increases of 129% in the United States and 73% in Europe, Ahold said.

“When you talk about what we are doing, on food and non-food platforms, it’s big growth on all fronts,” Chief Financial Officer Natalie Knight said in an interview.

Ahold expects online sales growth to continue to outpace traditional sales growth this year.

“We definitely believe we are going to continue to see very strong online growth in sales going forward. We are projecting a further growth of 30% in 2021, that includes 60% in the U.S,” she said.

Investments last year in distribution networks and pick up points for online orders, as well as other areas, would help boost capacity and increase sales, Knight said.

“It’s because we know that last year a lot of growth was still hampered by capacity ... we are continuing to build out capacity, so we are very confident the trend is going to continue,” Knight said.

At its online non-food retailer, which operates in Belgium, the Netherlands and Luxembourg, sales were projected to hit 5 billion euros for the first time in 2021, Knight said.

“Last year our goal was 3.5 billion. We hit 4.3 billion. Now for 2021 we are going to call out the 5 billion mark,” she said.

In its group outlook for 2021, Ahold said COVID-19 continued to create significant uncertainty and that a reduced number of reporting weeks in 2021 “will impact 2021 results.”

In 2021, the underlying operating margin is expected to be at least 4% and underlying per share earnings will grow by “mid- to high-single digits relative to 2019,” it said in a statement.

$1 = 0.8274 euros Reporting by Anthony Deutsch; Editing by Jason Neely and Edmund Blair