Egyptian President Mohamed Morsi arrives in neighbouring Sudan on Thursday for a visit which Khartoum has termed "historic" but which an analyst said should have come sooner.
The two-day trip is the Muslim Brotherhood leader's first to Sudan, which Egypt jointly ruled with Britain until 1956.
Morsi was elected last June after a popular uprising toppled longtime president Hosni Mubarak.
Official media in Sudan said Morsi is to hold talks with his fellow Islamist, President Omar al-Bashir, as well as political party leaders and members of the local Egyptian community.
"It is a historic visit because of the strategic depth of the relations between the people of the two countries, and both leaders are elected," Emad Sayed Ahmed, Bashir's press secretary, told AFP.
"On the contrary, it comes too late," University of Khartoum political scientist Safwat Fanous said, noting Morsi had already visited several other countries including India and Pakistan.
Bashir's press secretary said the visit "will complete some issues that have already been agreed" when the two leaders held talks in Cairo last September.
These include trade integration, transportation, investment, and the "four freedoms" pact, which gives citizens of each country the right to freely enter and conduct economic activities in the other. It has not been fully implemented.
"Both leaders will discuss how to coordinate their position in international forums," Ahmed added.
Sudan is an important ally for Egypt both in terms of its agricultural potential and in Cairo's efforts to secure an acceptable agreement with upstream Nile countries about the future of vital water supplies.
Two years ago, Egypt's then-prime minister Essam Sharaf said Egypt was the third largest investor in Sudan, with stakes valued at $5.4 billion.
Bashir's press secretary did not give more detail on the issues expected to be discussed but the two countries have delayed the opening of land border crossings. The also have a decades-old dispute over sovereignty of the Hala'ib Triangle along the Red Sea.
"Sudan is very important to Egypt, has been and will be in the future, for many reasons," Fanous told AFP.
He cited historical factors, the resources of the Nile river, and close ties between the two peoples.
Fanous suspects that Morsi's trip to Sudan has been delayed because his Muslim Brotherhood "deliberately wanted to keep a distance" from the internationally-isolated Bashir regime.
Khartoum has been under United States trade restrictions since 1997 over what the US said was support for international terrorism, efforts to destabilise neighbouring governments, and human rights violations.
In March, US Secretary of State John Kerry pledged $250 million in US aid to help revive Egypt's economy.
Morsi was due to land at about 1300 GMT.