Japanese gaming group Sega has offered to buy the creator of the popular Angry Birds franchise, Finland's Rovio, in a deal worth more than 700 million euros (HK$6 billion), the companies said on Monday.

The deal would mark the end the independence of Finnish mobile game makers, which burst into the scene when Rovio launched its slingshot-bird game more than a decade ago.

The bid by Sega, famous for its own animal character, Sonic the Hedgehog, is also the latest high-profile acquisition in the gaming sector.

The offer, which represents a 19 percent premium over Rovio's closing share price on Friday, is part of Sega's "long-term goal" of expanding into the mobile gaming market, Sega CEO Haruki Satomi said.

"Among the rapidly growing global gaming market, the mobile gaming market has especially high potential," he said in a statement.

Angry Birds instantly became one of the most successful mobile games ever released when it made its debut in 2009, with a variety of birds flying through the air to crash into structures and take down armies of green pigs.

In 2016, the "Angry Birds" movie, produced by Sony Entertainment, was a massive success that grossed US$350 million worldwide.

But Rovio has remained heavily reliant on its flagship game, struggling to develop another similar hit. In 2015, it laid off a third of its staff.

"Combining the strengths of Rovio and Sega presents an incredibly exciting future," said Rovio chief executive Alexandre Pelletier-Normand.

Rovio recommended that shareholders accept the offer. (AFP)