A small ferry carrying 20 protesters set sail from Cyprus for Gaza in a renewed attempt to challenge an Israeli blockade of the Palestinian territory, an activist group said on Monday.

Free Gaza Group organizer Ramzi Kysia said the Spirit of Humanity left the southern port of Larnaca on Monday morning.

The boat is expected to arrive in Gaza at around 2 p.m. (1100GMT) Tuesday and is carrying 3 tons of medical aid.

Passengers include former U.S. congresswoman Cynthia McKinney, Nobel Peace Prize laureate Mairead Corrigan Maquire and other activists from the Britain, Ireland, Bahrain and Jamaica.

Kysia says each passenger is also carrying a kilogram (2.2 pounds) of cement, an olive tree sapling, a water purifier, school materials and construction tools in a symbolic gesture of solidarity with Gaza's 1.4 million people.

"Gaza doesn't need charity, it needs the siege to be lifted," Kysia said.

The Group had planned to set sail for Gaza last week aboard two boats, but was delayed in resolving Cypriot authorities' safety concerns, Kysia said.

The Free Gaza Group has made five successful boat trips to Gaza since August 2008, defying a blockade imposed by Israel when Hamas won control of the territory in June 2007. Its activists were stopped twice by Israeli warships during Israel's three-week war in the territory in December.

The group says it plans more boat trips to Gaza this year.