Ijaz has no links to Pakistan and has a long record of spreading "poison" against Pakistan and the country's establishment and government, Gilani told reporters in Lahore.
Describing Ijaz as a person with "no credibility", the premier said it seemed "like some country's viceroy was coming (to Pakistan) and we have to deploy our army to protect him though he is not entitled to get such protocol under the Constitution and the law".
Asked about Ijaz's demand that the army should protect him for his appearance on January 24 before a Supreme Court-appointed commission investigating the memo issue, Gilani said it was the interior ministry's duty to protect Ijaz under the rules of business and the Constitution.
"Under the rules of business, the interior ministry will provide security and the civilian government can seek assistance, as and when required, from the Pakistan Rangers, the army and law enforcement agencies," he said.
Ijaz created a storm in Pakistan's political circles by making public an alleged memo that sought United States help to stave off a feared military coup in Pakistan last year.
Gilani said it was "uncalled for" to worry so much about Ijaz's claims. "The world will think we are so weak that on one article (written by Ijaz), the government falls and our institutions become weak," he said.
"We are sending a very wrong signal to the world that we cannot settle our matters and we will have to spend a lot of money on his security," he added.
The memo scandal is being investigated by the judicial commission and the Parliamentary Committee on National Security. Asked about Ijaz's reluctance to appear before the parliamentary panel, Gilani said, "I have to assist both of the commissions and I think in all fairness, he should appear before both."
Gilani said all the stakeholders, including the president, army chief and the Inter-Services Intelligence, had unanimously decided to refer the matter to the parliamentary panel but the Supreme Court later formed its own panel after receiving several petitions, including one from Pakistan Muslim League -N chief Nawaz Sharif.
Without naming anyone, Gilani said Ijaz was being treated in some quarters "like he is a head of state or a US President" who should be given protocol and provided security by the army. "This is not good for the country," he said.
Asked if Ijaz could be barred from leaving Pakistan, Gilani said he was a foreigner and the parliamentary and judicial commissions would have to decide this issue. "We have better things to do, we can't remain focused on
Ijaz. It is up to him whether he wants to come to Pakistan or he doesn't want to come to Pakistan, we don't care," he said.
Pakistan's former envoy to the US, Husain Haqqani, had resigned after the memo scandal became public, but no charge had been proved against him, Gilani said. "Till such time as the charges are proved, everybody is innocent," he added.
"The memo or anything else poses no danger to the country, but the message sent out to the world by this issue is a danger. A person with no credibility has shaken the country," Gilani said.