Egypt allowed lawmakers from the Muslim Brotherhood and other opposition groups to enter the blockaded Gaza Strip on Tuesday, but barred construction material contained in an accompanying aid convoy.
Security sources said this week Egypt would keep its Rafah border open "indefinitely".
However, Cairo still limits the items that can cross into Gaza, mostly to medicine and food, and only permits people seeking study or medical treatment to enter Egypt.
A global outrage erupted over Israel's bloody raid of an aid ship bound for the coastal enclave last week, renewing international calls to lift the blockade that has hit living conditions for trapped Gaza's 1.5 million residents.
"Egyptian authorities allowed us to cross into Gaza in solidarity with Palestinians there, but they held back the aid intended to break the blockade and help rebuild the Strip," Brotherhood parliamentarian Mohamed Beltagy said.
The lawmakers, two of whom belonged to Egypt's opposition Karama Party, were granted a 24-hour stay in Gaza.
Opposition groups have accused Egyptian authorities of complicity in the Israeli blockade and have demanded a full, unrestricted opening of the border.