After his release on Tuesday he told journalists: "I am free again, but my homeland is still a prison."
Reuters news agency reported he was slurring his speech because of a missing tooth.
He went on to say he had suffered beatings, whippings, electric shocks and simulated drowning at the hands of officials and guards.
"At the time that Prime Minister Nouri Maliki said on television that he could not sleep without being reassured on my fate... I was being tortured in the worst ways, beaten with electric cables and iron bars," he said.
He demanded an apology from Mr Maliki and said he would name the officials who tortured him in due course.
ANALYSIS
Hugh Sykes, BBC News, Baghdad
Many Iraqis regard Muntadar al-Zaidi as a national hero - others think he was unforgivably rude.
After leaving prison, Mr Zaidi went straight to al Baghdadiya, the TV station he was working for at the news conference where he threw the shoes.
Addressing his own news conference, he said he had been tortured in jail.
A spokesman for the ministry of human rights told us that if he was badly treated, it's likely that it happened while he was in custody before his trial, and not in the prison where he spent the past nine months, as it is a jail with a good reputation.
He also said he feared US intelligence services regarded him as an "insurgent revolutionary" and would "spare no effort" in a bid to kill him.
"I want to warn all my relatives and people close to me that these services will use all means to trap and try to kill and liquidate me either physically, socially or professionally," he said.
His allegations of abuse mirror claims made earlier by his family, who said he had been beaten, suffering a broken arm, broken ribs and internal bleeding.
The Iraqi military earlier denied the allegations, but following Zaidi's news conference Sami Al Askari, an adviser to Mr Maliki, said his torture claims should be investigated.
Zaidi's family has been preparing to throw a party for him.
He has reportedly received offers of money, jobs and even marriage from across the Arab world.
His relatives say he was offered a golden horse by the Emir of Qatar.
Zaidi shouts "this is the end" as he throws his shoes at President Bush
When news of his release filtered through to his family's home in Baghdad, there was an eruption of celebration, with women dancing and singing.
'Goodbye kiss'
The shoe-throwing incident came during a joint news conference between Mr Bush and Mr Maliki.
As he threw the shoes, Zaidi shouted: "This is a goodbye kiss from the Iraqi people, dog.
"This is from the widows, the orphans and those who were killed in Iraq."
In an interview afterwards, Mr Bush insisted he did not harbour any ill feeling about it.
"It was amusing - I've seen a lot of weird things during my presidency, and this may rank up there as one of the weirdest," he said.
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