LONDON - TUI Group , the world's biggest holiday company, said it was expecting a strong 2021 holiday season and stuck to a plan to operate 75% of its pre-pandemic capacity, as rising vaccination levels mean Europe will open for travel this summer.

But ongoing restrictions and COVID-19 uncertainty have so far held back an expected surge in demand for trips. TUI said that it had a total of 2.6 million bookings for this summer, 69% lower than it had at this time of year in 2019.

TUI, which before the pandemic took 23 million people on holiday annually, was left disappointed by the limited re-opening of travel in Britain, which along with Germany is one of its two biggest markets.

Britain said that people could travel to Portugal without needing to quarantine, but kept some of TUI's most popular destinations like Spain and Greece off its green list of low risk destinations.

TUI said, however, that it expected those destinations to open in the next few weeks and that demand had recently picked-up, with new bookings doubling since April.

"We are now at the beginning of the expected restart. The anticipation is palpable, these are opportunities for tourism and for TUI," chief executive Fritz Joussen said in a statement.

Since the pandemic struck Europe last February, Germany-based TUI has been hammered, relying on multiple bail-outs from the German government to survive.

Reporting results for the six months ended 31 March 2021, TUI said on Wednesday that it sunk to an EBIT loss of 1.3 billion euros ($1.58 billion) on revenues which contracted 89% to 716 million euros.

($1 = 0.8249 euros)

(Reporting by Sarah Young; Editing by Alistair Smout/Guy Faulconbridge) ((sarah.young@thomsonreuters.com; +44 20 7542 1109; Reuters Messaging: sarah.young.thomsonreuters@reuters.net))