"Egypt and Sudan on the other side, insist such entity must abide by a long-standing agreement from 1929."
Egypt has said securing water is an issue of national security and is vital to the country's agriculture, which accounts for more than 80 per cent of Egypt's water consumption.
But other Nile river basin countries have called for a more equitable distribution of the water to support power generation projects and agricultural growth.
Mohamed Nasreddin Allam, Egypt's water minister, has repeatedly said Egypt would not compromise on its rights to the vital waterway.
Speaking on the sidelines of the annual meeting, he said it did not matter if other Nile Basin countries were not convinced of the rights given to Egypt under previous agreements.
"It doesn't matter if they are convinced ... it matters that we are convinced," he was quoted by the Reuters news agency as saying.
Egypt's cabinet issued a report last week that the country needed 86.2 billion cubic metres of water in 2017 and only has resources of 71.4 billion cubic metres.
Rageh said Egypt's rights over the Nile were not officially on the agenda of the conference, but were raised by many of the speakers.
The Nile and its tributaries flow through Burundi, Congo, Eritrea, Ethiopia, Kenya, Rwanda, Sudan, Tanzania and Uganda, as well as Egypt.
Talks in Kinshasa last month ended with Egypt refusing to ratify a new pact over water sharing without the other signatories explicitly agreeing to its original share of Nile water and a veto for Cairo over any future upstream projects.
Due to the absence of any major dams or hydroelectric projects upstream of it, experts say Egypt can afford to be dismissive of the other states' concerns since there is little they can do to impede the flow of the river.
Cairo was given the right to veto projects further up the Nile under a 1929 agreement between Egypt and Britain, acting on behalf of its then east African colonies.
It was also awarded the largest share of any country along the river in a 1959 agreement with Sudan, allowing it to consume 55.5 billion cubic metres of Nile water every year - the largest share of its estimated 84 billion cubic metres.