Preparations for the Paris Olympics stepped up a gear on Saturday as security teams scoured the banks of the Seine ahead of Friday's opening ceremony and top International Olympic Committee officials met in the French capital.

Police with sniffer dogs checked the six-kilometre (four-mile) route along the Seine for the ceremony in which around 6,000-7,000 athletes will sail on nearly a hundred barges and river boats in front of 300,000 spectators.

French police will be bolstered by colleagues from several countries, including Spain, Britain and Qatar.

Early on Saturday, a rehearsal for the ceremony was held on the river but security barriers and police screened it from the eyes of residents and media.

The stakes are high for the waterborne parade; the first time the opening ceremony of a Summer Games will take place outside a stadium.

The preparations for the ceremony have caused extensive disruption to residents of central Paris, who must have a pass with a special QR code to cross the Seine.

"We've had far fewer customers than usual for the last two weeks. There aren't many tourists and lots of Parisians have left town. All our local clientele has gone," said Behi Samadian, 69, in a boutique in Saint-Germain-des-Pres.

Team delegations have started to check into the athletes' village but some arrivals were delayed by Friday's global IT crash.

"Like a lot of organisations, we suffered this global Microsoft outage," the Games chief organiser Tony Estanguet told reporters on Friday.

"All of our servers were affected this morning."

However the accreditation systems were working again by Friday evening.

In better news for organisers, the ticketing systems were not affected.

Organisers say 8.7 million tickets have already been sold, beating the record from the 1996 Atlanta Olympics and that figure will rise because tickets are still on sale for some of the 45 sports.

Some of the athletes expected to be the biggest stars of the Games, including American sprinter Noah Lyles, will compete for a final time before the Olympics at the Diamond League meeting in London on Saturday.