Chief Executive Niels B. Christiansen said years of investment had paid off just in time for the pandemic, with an improved online sales system and new sets to build from plastic bricks, such as robots that can be programmed on a smartphone.

"COVID has accelerated trends that were already in motion. More people shopped online," he said. "We've seen more families at home building together."

Lego has been searching for years for a formula to revive a decade-long double digit growth streak that came to an end in 2017. That year the family-owned firm hit the reset button, bringing in Christiansen as CEO.

Sales last year grew 13% to 43.7 billion Danish crowns ($6.98 billion), up from 6% growth in 2019, while operating profit rose 19% to 12.9 billion crowns, Lego said in a statement.

"For the past two years we've made large-scale investments in initiatives designed to support long-term growth," Christiansen said.

"In 2020, we began to see the benefits of these, especially in e-commerce and product innovation."

Lego would hire "several hundred" employees to boost digitalisation further in 2021, Christiansen told Reuters.

He declined to say how much online sales grew last year, but said the number of visitors on Lego.com doubled to more than a quarter billion in a year.

Rival toy maker Mattel, behind the Barbie brand, in February reported 2% annual net sales growth for 2020, while Hasbro, the maker of Monopoly, saw net revenue decline 8% for the year.

Christiansen said Lego gained around 1 percentage point of market share globally, picking up in most of its markets.

The firm also increased its number of physical stores by 134, including 91 new outlets in China, its biggest growth market. The company expects to open 120 stores in 2021, 80 of those in China.

($1 = 6.2570 Danish crowns)

(Reporting by Nikolaj Skydsgaard; Editing by Peter Graff)

By Nikolaj Skydsgaard