But the Mubarak family are not thinking of putting forward the president's 42-year-old son Gamal as a successor, adviser Osama el-Baz said on Tuesday.
Mubarak is 78 in May and has ruled Egypt since 1981.
Baz said: "He will remain, so long as he's able, capable and so on. But if he finds that there is another group of people, another person, who are willing to carry the torch, I have the feeling that he would welcome it."
"It's not clear yet who can take over. Nobody can say, and definitely the president and his family are not thinking about succession. They don't think of Gamal taking over and he does not give himself more rights than other Egyptians," he added.
Opposition leaders say they are convinced that the Mubaraks are planning to install Gamal Mubarak as president through the ruling party, which under present conditions is the only party able to nominate a candidate in presidential elections.
Gamal Mubarak is expected to
seek presidency within two years
Gamal, a former banker, has been promoted to the position of assistant secretary-general of Mubarak's National Democratic Party (NDP), which maintained its control of parliament last year despite inroads by the opposition Muslim Brotherhood.
Brotherhood deputy leader Mohamed Habib last month told Reuters he expected Gamal to seek the presidency within two years, while the NDP still controls local councils.
Any independent seeking the presidency would need endorsements from at least 140 local council members, a condition none could meet at least until council elections take place in early 2008, two years later than originally planned.
Baz, who has advised three successive Egyptian presidents since the 1960s, said being president was especially difficult these days but, as a military man, Mubarak would not give up.
"The international situation is unclear, unstable and the demands of the population in every place are growing. So you have to meet these demands.
"But President Mubarak is a soldier and a soldier cannot run away from responsibility, cannot say: 'To hell with you ... I'm sick and tired of it'," Baz said.