In a statement on Monday afternoon, cave rescue service Speleo-Secours Schweiz said given the height of the water and the weather forecast, the group were unlikely to be able to get out of the cave for another 48 hours at the earliest.
In a press conference Franz Auf der Maur from Speleo-Secours Schweiz said “it could take a week” to get them out, reported 20 Minutes.
The amateur cavers, aged 25 to 55, set off on Saturday morning with an experienced professional guide for a two-day bivouac excursion inside the Hölloch cave network near Lucerne, one of the largest caves in the world.
But the group became trapped by rising water and were unable to leave the cave as planned on Sunday.
A team of four rescuers was sent out and reached the group after eight hours, using a different route that is much more demanding, meaning the amateur cavers cannot use it to leave.
All the trapped men are safe and well, said the rescue service. They are being offered psychological support.