The Egyptian pound fell to an all-time low against the dollar on Monday, just hours after President Morsi sought to further downplay concerns over the economy, dpa reported.
The pound fell to 6.34 to the dollar.
"The pound's fall does not worry or frighten us, and within days things will balance out," Morsi was quoted in state media as having said late Sunday.
"The market will return to stability."
It was the second time in a few days that Morsi had to defend the economy, which he earlier said grew by 2.6 per cent in the third quarter.
His remarks come after the credit rating agency Standard & Poor's cut Egypt's long-term rating to B- and as the pound plummets in the wake of the introduction of new rules in foreign currency sales.
The opposition has meanwhile been calling for mass rallies on Tuesday against new legislation on public protests, which it says will limit freedoms.
Egypt has seen violent protests over a draft constitution. At least nine people have been killed in street battles between supporters and opponents of Morsi's policies.