"It is essential that we take steps to eliminate both access to and production of material for nuclear weapons," ElBaradei, the director-general of the Vienna-based International Atomic Energy Agency (IAEA), told the UN General Assembly
He was presenting the IAEA's annual report to the 191-nation UN assembly.
The assembly called in 1993 for negotiation of such a pact - also known as the Fissile Material Cut-off Treaty.
But talks have never gotten off the ground, and last July the Bush administration said it no longer wanted verification measures in the treaty because they would be too costly and unreliable.
ElBaradei also expressed disappointment that neither last May's Non-Proliferation Treaty review conference nor last month's World Summit reached any new agreements on measures to curb the spread of atomic arms and promote disarmament.
Agreements were blocked at both meetings by a clash of interests among various governments and blocs.
The US sought to highlight its concerns about Iran's nuclear programme and play down new disarmament commitments, while Iran pushed the right of developing nations to harness nuclear energy.
Iran says its nuclear reactors are
to be used to harness energy
Egypt pushed for a crackdown on Israel's presumed but undeclared nuclear arms, and non-aligned nations pressed the major powers to agree to eventually destroy all their atomic weapons.
"The current challenges to international peace and security, including those related to nuclear non-proliferation and nuclear arms control, cannot be wished way," ElBaradei said.
"It is urgent and indispensable that we continue to build a global security system that is both equitable and inclusive."
Among his agency's top priorities for the coming year were to convince North Korea, which has pulled out of the Non-Proliferation Treaty and declared it has nuclear bombs, to return to the treaty's control regime, and to obtain assurances from Iran about the goal of what Tehran insists is a peaceful nuclear program but which others say aims to make weapons.