The delegation, which includes 55 parliament members of 12 European countries and the European Union, crossed into Gaza on Friday afternoon through Rafah border crossing with Egypt.
Hamas said it is the first ever visit of such high-ranking European parliamentary delegation to Gaza since Hamas seized the control of the impoverished enclave in June 2007.
Hamas lawmakers received the delegation at Rafah crossing. The European parliamentarians called for the immediate end of the Israeli blockade on the Gaza Strip.
British member of parliament Sir Gerald Kauffman told a news conference at Rafah crossing that the visit of the delegation "is a message of solidarity with Gaza to end the Israeli siege."
"Our suffering to arrive here is nothing compared with the longsuffering of Gaza Strip population due to the suffocating unfair Israeli siege imposed on them," said Kauffman.
As for the major Israeli offensive on Gaza last winter, he said "anyone uses the white phosphoric against civilians must be taken to court for war crimes."
Meanwhile, Arafat Madi, chief of the European Campaign to challenge the Israeli blockade told reporters that the delegation "has a common goal, which is expressing solidarity with the Palestinian people."
Deputy Speaker of the Hamas-dominated parliament, who received the delegation, told reporters that the visit of the European parliamentarians "is an opportunity to show them the suffering of 1.5 million (Gaza) people."
Israel has been imposing a tight blockade on the Gaza Strip since Hamas seized control of the enclave by force and routed moderate Palestinian President Mahmoud Abbas' security forces.