US Secretary of State Hillary Clinton will urge Egypt's civilian and military leaders to work together to complete a full transition to democratic rule, senior US officials said on Saturday.

Clinton arrived in Cairo to meet Egypt's newly-elected Islamist President Mohamed Morsi on Saturday and military chief Field Marshall Hussein Tantawi on Sunday, two of the central players in the power struggle playing out in the country.

"She is going to say, you have to stick with it. You have to keep going," a senior US official, speaking on condition of anonymity, told reporters travelling with Clinton.

"It is crucial that all of the stakeholders who need and have a voice in Egypt's transition engage in a dialogue to answer the complicated questions around parliament and the constitution.

"So she will encourage Tantawi, as she will encourage Morsi, and civil society, to engage in that dialogue and to avoid the kinds of confrontation that could potentially lead to the transition veering off track," the official added.

The United States lent its support over three decades to Egypt's long-time authoritarian ruler Hosni Mubarak, who was driven from power on 11 February 2011.

Clinton will be the most senior US official to meet with Mursi, an Islamist who emerged from the country's long-oppressed Muslim Brotherhood movement to be inaugurated as president two weeks ago, after what was regarded as the country's first relatively free and fair presidential election.

The army, in power for six decades, moved to limit the power of the new civilian president even as voters were lining up to elect him.

On the first day of a two-day run-off election last month, generals dissolved the parliament. On the second day, they issued a decree restricting the president's powers.

Shared interest

Morsi did not wait long to assert his own power, either, issuing a decree summoning the disbanded, Islamist-led parliament just days after he took office.

The lawmakers met on Tuesday. Judges, seen as allies of the generals, responded by rebuking Morsi.

The political confrontation risks paralysing the government, and the first casualty could be Egypt's fragile economy, fast heading towards a balance of payments and budget crisis.

The past year-and-a-half of turmoil has frightened away tourists, sent investors fleeing and wrecked economic growth. Egyptians need their leaders to set aside their political quarrel fast.

Asked why the Muslim Brotherhood should be interested in working with the United States, a senior US official argued the two countries have a shared interest in strengthening Egypt's economy and in maintaining peace and security.

During Mubarak's rule, which was supported by the United States, he imprisoned many of its leaders and assiduously worked to marginalise the group.

Egypt's peace treaty with Israel has been a cornerstone of regional security for a generation and ushered in an era of extensive US foreign aid to Egypt, now running at about $1.55 billion a year.