Haqqani's wife and member of the National Assembly Farahnaz Isfahani Monday said they were contemplating legal action.
Haqqani met Zardari Sunday and spoke to him about the secret memo. He then expressed his willingness to hand over his BlackBerry for investigation, reported Geo News.
Pakistani businessman Mansoor Ijaz alleged last month that a senior Pakistani diplomat asked for help in getting a message from Zardari to then chairman of the US Joint Chiefs of Staff, Admiral Mike Mullen.
Ijaz alleged that Zardari feared a military takeover following the US raid that killed Osama bin Laden in his hideout in Pakistan town of Abbottabad May 2.
The businessman says he has phone records of calls allegedly from Haqqani and his US contact between May 9 and 10.
Haqqani told Geo News that he was unable to understand the claims made by Mansoor Ijaz.
While raising several questions, Haqqani asked why Mansoor Ijaz had sent the memo and who delivered that to Mullen. He also wondered as to how it was proved that he had authored the memo.
Farahnaz strongly defended her husband.
She told reporters outside the Supreme Court they were planning legal action.
She and her husband want "an investigation" and were willing to cooperate in the forensic examination of Husain Haqqani's BlackBerry phone and computer.
"Whatever guidance is given to us by our senior leadership, we will take it, but personally if the senior leadership allows us, we will go in for libel," she said.
Prior to the memo issue, the Pakistan Army and the Inter-Services Intelligence (ISI) were upset with Haqqani over issuance of visas to Americans without "prior scrutiny" by the Pakistani security agencies.
Before leaving Washington for Pakistan, Haqqani met US special representative to Pakistan and Afghanistan Marc Grossman.
