He said his security detail was removed, and his phone and Internet service had been cut.
Jordanian Foreign Minister Ayman Safadi said at a press confrence on Sunday that Prince Hamzah had held contacts with unnamed foreign intelligence and was seeking to depose the current King Abdullah II.
In this file photo taken on April 17, 2012 shows Jordanian Prince Hamzah bin al-Hussein, president of the Royal Aero Sports Club of Jordan, carries a parachute during a media event to announce the launch of "Skydive Jordan", in the Wadi Rum desert.
Any bid and conspiracy to spread anarchy and instability in Jordan and any other Arab country can not be tolerated, he added.
Labib Kamhawi, a Jordanian analyst, told the Associated Press that Hamzah likely crossed a line for the royal family by indicating he might be an alternative to the long-ruling king.
Arrests of top officials and royal family members are rare in Jordan.
Hamzah is the eldest son of late King Hussein and his American wife Queen Noor.
Hamzah, 41, had on Saturday released a video message via the BBC in which he accused Jordan's rulers of nepotism and corruption and charged that he had been placed under house arrest.
Speaking in English in the video recording, passed by his lawyer to the BBC, Prince Hamza said the country's leaders were a corrupt few who put their interests above the public.
"I'm not part of any conspiracy or nefarious organisation or foreign-backed group, as is always the claim here for anyone who speaks out", he said.
Jordan's army chief said on Saturday that Hamzah was not under arrest, but had been asked to stop "some activities that could be used to shake the stability and security of Jordan". Jordan, Saudi Arabia and Egypt, all Sunni-majority countries, have for years aligned together against Shia Iran.
The oil-rich GCC states are key backers of resource-poor Jordan, which depends heavily on external aid.
The US state department has already offered the king, who has cultivated close relations with Washington and been a key ally in the war against Islamic State, its "full support".
Jordan has few natural resources and its economy has been hit hard by the Covid-19 pandemic.
"What Prince Hamzah said is repeatedly heard in the homes of every Jordanian", said Ahmad Hasan al Zoubi, a prominent Jordanian columnist.
Kuwait's foreign ministry expressed its support to all measures taken by King Abdullah and his crown prince to maintain the security and stability of Jordan, adding "the security and stability of the kingdom are that of Kuwait".
"Jordan's safety and stability is the priority".
In early 2018, as then-President Donald Trump was threatening to cut aid to countries that did not support US policies, the administration boosted assistance to Jordan by more than $1 billion over five years.
Abdullah had appointed Hamzah crown prince in 1999 in line with Hussein's dying wishes, but in 2004 stripped him of the title and gave it to his own eldest son Hussein. The move was seen at the time as part of Abdullah's consolidation of power five years after the succession.