Planning Minister Basim Awad Allah has tendered his resignation to the prime minister, Khadir said.
She did not expand on why Awad Allah, who is also a minister for international cooperation, wanted to leave the government.
"He just wanted to leave," Khadir said on Saturday. She said a successor was likely to be named soon, possibly tomorrow.
It was not immediately clear if Awad Allah had personal differences with Prime Minister Faisal al-Fayiz, who took office on 25 October 2003.
Rumours surfaced recently suggesting that Awad Allah opposed the way al-Fayiz was running state affairs, including the economic policy.
In a meeting with Awad Allah and other state economists on Thursday, Jordan's King Abd Allah II had commended the Planning Ministry and its implementation of socio-economic projects in the country. "He expressed assurance over the work of the ministry," Jordanian newspapers reported on Friday. Awad Allah has not been available for comment.
His resignation will have little effect on Jordan's economic planning, said Fahd al-Fanik, a well-known Jordanian economist.
"Our economic policy is stable" under an agreement with the International Monetary Fund (IMF), he said. The IMF had supervised reforms since 1989 to ease the country's debt burden. The programme ended in July last year.
Al-Fanik said Awad Allah had been "feeling weak" since he was attacked in parliament during a budget debate last week for his planning strategy.
It was not clear if al-Fayiz had
differences with Awad Allah
Several lawmakers argued his ideas favoured private enterprise and emulated US-backed plans in the kingdom. "The king used part of his political capital to try to bolster Awad Allah," al-Fanik said, referring to Thursday's royal visit to the Planning Ministry.
Awad Allah is a close confidant of Abd Allah and served as an economic strategist under the monarch for at least three years until he took his Cabinet portfolio in 2003. A US college graduate, he was considered as one of the top planning strategists in Jordan, a cash-strapped nation saddled by recession and foreign debts.
Awad Allah's duties entailed planning socio-economic, infrastructure and local development projects and negotiating international assistance to Jordan, including signing financial agreements with donor countries such as the United States.