Hamas has said the United Nations call for aid groups to send supplies to the Gaza strip over-land rather than by sea amounts to "collaboration with the Israeli occupier".
"The UN call to international organisations to use the over-land road to Gaza instead of the sea is unacceptable and illegal," Sami Abu Zahri, a Hamas spokesman, said on Saturday.
On Friday, the UN said groups delivering aid to Gaza should send it over land, after Israel warned that it would continue to intercept ships trying to break its naval blockade of the Palestinian enclave.
"There are established routes for supplies to enter by land. That is the way aid should be delivered to the people of Gaza," Martin Hesirky, a UN spokesman, told a news briefing.
"Our stated preferance has been and remains that aid should be delivered by established routes, particularly at a sensitive time in indirect talks between Palestinians and Israelis," Nesirky said, in reference to proximity talks between Israel and the Palestinain Authority based in the West Bank.
Hamas, which is not participating in proximity talks, said that most Gaza residents "are still banned from leaving the territory and this is why this call [by the UN] is considered a contribution to the [Israeli] blockade".
Groups trying to deliver aid to the Hamas-ruled coastal enclave should "continue to reach Gaza by sea until the blockade is really broken," Abu Zahri said.
Israel, which faced international condemnation over its May 31 raid on an aid flotilla that killed nine Turkish activists, has warned that its forces will continue to board ships attempting to deliver supplies to Gaza.
Ehud Barak, the Israeli defence minister, renewed that warning on Friday, stating the navy would prevent Lebanese aid ships from reaching Gaza.
"If this flotilla does leave Lebanon and refuses to be led by our navy to the [Israeli] port of Ashdod, we will have no other choice than to arrest it at sea," Barak said.