Pakistani government officials said Zardari traveled to the city in the United Arab Emirates emirate of the same name Tuesday because he has a pre-existing heart condition and to visit his children, The Washington Post reported.
His trip sparked speculation the embattled Zardari would step down for health reasons or because the Pakistani military demanded it.
Zardari spokesman Farhatullah Babar said Wednesday such claims were "speculative, imaginary and untrue." Others close to Zardari said he would return to Pakistan soon.
Zardari had been expected to testify to parliament over the latest scandal to rock his shaky and unpopular government. At issue is a memo that asked Washington to help prevent a Pakistani military coup after the May killing of al-Qaida leader Osama bin Laden in Pakistan.
The Pakistani-American who delivered the memo to U.S. Joint Chiefs of Staff Chairman Adm. Mike Mullen said the memo was written by a member of Pakistan's diplomatic corps to the United States and had Zardari's backing. Pakistani Ambassador to the United States Husain Haqqani has denied any involvement but resigned under pressure in November.
Members of Zardari's Pakistan People's Party said rumors of Zardari's resignation were proffered by opposition politicians, the Post said.
"This is another addition to the propaganda against the president," said one party insider who spoke on the condition of anonymity.