The United States has urged Egypt to fully implement the rights guaranteed by its newly approved constitution, saying that democracy is more than one election.

Egyptians overwhelmingly approved the charter in a referendum last week by more than 98 percent, in what the government hailed as a public seal of approval of the overthrow of Islamist president Mohamed Morsi.

However, US Secretary of State John Kerry warned that "It's not one vote that determines a democracy."

"It's all the steps that follow… it's what comes next that will shape Egypt’s political, economic and social framework for generations," he added in comments on Saturday

"As Egypt’s transition proceeds, the United States urges the interim Egyptian government to fully implement those rights and freedoms that are guaranteed in the new constitution for the benefit of the Egyptian people, and to take steps towards reconciliation,” Kerry said.

US officials and lawmakers are expected to unfreeze suspended aid to Washington’s key Middle East ally provided that the US administration certifies last week's referendum and that Egypt is progressing in a democratic transition.

"The brave Egyptians who stood vigil in Tahrir Square did not risk their lives in a revolution to see its historic potential squandered in the transition," Kerry said, urging Egypt's political leaders to "make difficult compromises and seek a broad consensus on many divisive issues."

The senior diplomat called on the interim Egyptian government to take into account concerns made known by international organisation monitoring last week's poll as the country prepares for presidential and parliamentary elections.

He cited preliminary assessments by Democracy International and the Carter Center that underpinned challenges including, "Egypt’s polarised political environment, the absence of a fully inclusive process in drafting and debating the constitution and arrests of those campaigning against the constitution."

Morsi's Muslim Brotherhood movement and its Islamist allies boycotted the vote, which will be followed by presidential and parliamentary elections.

The vote is expected to smooth the path for army chief Abdel-Fattah El-Sisi, encouraged by millions who backed Morsi's ouster and approved the new charter, to stand for the presidency

The constitution will replace an Islamist-drafted document signed into law by Morsi in 2012 after it was passed in a referendum.