LONDON/COPENHAGEN, Jan 31 (Reuters) - Novo Nordisk will target launches of its mega popular obesity shot Wegovy in markets where it already has strong sales of its older weight-loss drug Saxenda, CEO Lars Fruergaard Jorgensen said, as it faces growing competition from U.S. rival Eli Lilly.

Lilly won approval in November in the U.S., Britain and the European Union for its obesity drug Zepbound, and Novo and Lilly's drugs are the most effective treatments for weight loss approved to date.

In his first detailed comments on how competition is affecting his company's strategy for its Wegovy blockbuster weekly injection, Jorgensen said the Danish drugmaker is watching Lilly's launches. "I think most likely they have a situation like ours where they're building capacity and have to look at tactics market by market," he told Reuters in an interview on Wednesday.

"They I'm sure look at what we do, and we will be looking at what they do. That's how competition plays out."

Jorgensen has previously said that he welcomes competition, and that there is room for multiple drugs in the fast-growing obesity drug market, which analysts predict could be worth more than $100 billion by 2030.

Novo on Wednesday forecast another year of double-digit growth as it boosted U.S. supplies of Wegovy.

The company is now going head-to-head against Lilly's drug in the U.S. and Germany, and Lilly said last week it would launch in Britain "within weeks".

In January Lilly also launched its weight-loss drug - sold as Mounjaro in Europe - in Poland, where Novo has not yet rolled out Wegovy. Jorgensen said he was not aware that Lilly had launched in Poland.

Novo has launched Wegovy in eight countries including Germany and Britain since its debut in the U.S. in 2021, with its most recent launches in Switzerland and the United Arab Emirates, both in November.

Jorgensen told Reuters that the decision to launch in its most recent markets was driven in part by the fact that Novo had already established its obesity business in those countries.

"It’s easier to start there, compared to markets say where we do not have strong Saxenda sales," he said.

Saxenda, Novo's older and less effective weight-loss drug, has seen a jump in sales since Wegovy fell into shortage after its launch in the U.S. on runaway demand.

Jorgensen reiterated that launches of Wegovy in more European countries, which tend to have single-payer public health systems, will be "controlled".

Novo aims to sign agreements with European governments to guarantee some supply goes to the most vulnerable patients who cannot afford to pay out of pocket.

(Writing by Maggie Fick; Editing by Jan Harvey)