Hun Sen has said that people posting online messages online saying they will not vote in the election on July 29 could face legal action.
Representatives of major mobile phone operators covered by the order could not be reached for comment.
Ouk Phalla was one of the country’s most prominent Apsara dancers.
Two candidates in next month’s election amongst those targeted in new report.
The hearing, held on June 14, invited experts to testify as to the health of democratic regimes seen as “backsliding” towards authoritarianism.
Young Cambodians are eager for change and represent a large voting demographic, but their growing activism can also put youths at risk.
The prince and his wife, Ouk Phalla, 39, were traveling to meet supporters in the southwestern province on Sunday morning.
Some 8.4 million Cambodians were registered to vote in the election, according to the latest voter lists.
Prime Minister Hun Sen and other senior ruling Cambodian People’s Party figures have labeled those participating in the boycott as “traitors”.
US targets General Hing Bun Hieng, a member of the prime minister’s inner circle, ahead of election.
Sao Sokha has previously attributed his success in the security forces to an affinity with the methods employed by German Nazi leader Adolf Hitler.
A demonstration is planned in the United States on June 16, while similar protests are also being called for in European countries and Japan and South Korea.