Deputy Prime Minister Marwan Moasher told a news conference on Sunday that the woman, who was to have been a fourth bomber, would appear on Jordanian television to explain details of the attacks that killed 57 people.
The woman is suspected of being involved in the preparation of the attack on the Radisson SAS hotel, one of three hit in Wednesday's bombings that have sharply jolted Jordan, one of the most stable countries in the Middle East.
"She took part in preparing an attack by her husband on the Radisson Hotel by bringing explosives into the hotel," another Jordanian official said.
Moasher identified the woman as Sajida Mubarak al-Rishai and said she was the sister of a key aide to al-Qaida's Iraq leader Abu Musab al-Zarqawi, a fugitive Jordanian who is Iraq's most wanted man.
He said she failed to blow up her explosives charge in the hotel ballroom where a wedding reception was in full swing.
Marwan Moasher said the woman
brought explosives into a hotel
"Her husband asked her to leave the wedding party. Once she did he detonated himself successfully," Moasher added.
He showed pictures of the explosives belt worn by the woman, which he said show "the metal balls that were also attached to the belt so that they can inflict the largest number of casualties".
He said she was the sister of al-Zarqawi's "amir" in the western Iraqi province of al-Anbar who was killed in Falluja.