The group has reported that the ship Juliano has been sabotaged while berthed in Piraeus harbour, in Greece.
“It is time for the international community to put their foot down and say: It's enough!” said Swedish spokesperson Mattias Gardell in a statement on Monday.
According to Mikael Löfgren, press coordinator of the organisation, it is not known who was behind the attack in which hostile divers destroyed the propeller housing and severed the two propeller axles beneath the boat.
“We didn't catch anyone in the act, so we can't be 100 percent sure, but we have our suspicions,” said Löfgren to The Local.
Löfgren said that the only thing they could be sure of was that the perpetrators would be representing those who don't want them to succeed in their mission.
And within the Norwegian organisation, who are co-owners of the ship, they are thinking along the same lines.
“All we know is that Israel is doing everything in its power to slow us down,” said Norwegian spokesperson Torstein Dahle to Norwegian daily Dagbladet.
Investigations carried out by Ship To Gaza's own divers show that the damage can be repaired in time for the ship's planned departure at the end of the week. But according to Löfgren it will cost €12,000 ($17,000) -15,000 to fix.
According to Gardell's statement, the organisation suspects that foreign powers are exerting pressure on Greece to delay the flotilla's passage.
And if this is a matter of foreign agents operating on Greek soil, he thinks the international community should act, while Mikael Löfgren argued that the solution was simple.
“It is not so much a question of dealing with the sabotage to our boat. The impending question is really to urge Israel to end the blockade - then our problem would disappear by itself,“ Löfgren told The Local.
The ship Juliano is jointly owned by the Swedish, Norwegian and Greek Ship to Gaza organisations. It is one of the smallest boats in the Freedom Flotilla and has room for 25 passengers.
According to earlier statements from the organisation, 20 Swedes will take part in the action, among which will be Swedish thriller writer Henning Mankell, an MP and a midwife.
The flotilla is the second international operation put together by the Freedom Flotilla organisation after a prior attempt to sail to Gaza in May 2010 was prevented by the intervention of armed Israeli forces, resulting in the death of nine activists and prompting international condemnation of Israel.