Five European parliamentarians said Wednesday that Israeli authorities had prevented them from entering the Gaza Strip.
"The refusal of access to Gaza by the Israeli authorities to the European Parliament on arbitrary grounds is unacceptable," Cypriot MEP Neoklis Sylikiotis said in a statement.
Similar delegations of European lawmakers have been barred from entering the Palestinian coastal enclave since 2011, the statement added, though a team led by the head of the European Parliament's budget committee was allowed to visit once.
"What is there to hide from us?" it said, condemning what it called "systematic" entry bans.
Israel, which controls all access to empoverished Gaza apart from its southern border with Egypt, explained parliamentarians were not among those allowed to enter the territory.
"Israeli policy allows professional and humanitarian officials to cross between Israel and the Gaza Strip for the development of the Gaza Strip in the field of economy and infrastructure, in addition to foreign diplomats serving in the Palestinian Authority or Israel," the defence ministry body responsible for approving entry told AFP.
Sylikiotis dismissed the explanations as "unacceptable", calling on the international community to pressure Israel to lift the blockade of Gaza.
The European Union is the largest donor of financial aid to the Palestinians.
The World Bank and the United Nations say a decade-long blockade of Gaza has killed virtually all exports and severely damaged the enclave's economy.
The blockade, coupled with the almost permanent closure of the Egyptian border, impacts almost all the two million inhabitants of the Gaza Strip.
Israel says it is necessary to constrain Hamas, the Islamist movement that runs Gaza.