That's the deadline the government gave the paper when it slapped it with a $6.3 million tax bill last month, accusing it of failing to pay that amount in taxes over the past decade.
He urged other nations to put pressure on Mr. Hun Sen.
The Daily has been operating legally in the country since its founding in 1993 by American journalist, Bernard Krisher.
The case appears to be based on a four-year-old video of Mr. Kem Sokha, in which he says in a speech that he received advice from the United States on how to build an opposition movement.
CNRP President Mr Sokha was arrested in the early hours of Sunday on allegations of treason and was sent to be detained in a prison in Kbong Khmum province, which is about 80 kilometres from Phnom Penh.
He said the next step will be his court appearance to officially face the charges, which carry a prison sentence of 15 to 30 years.
The government appeared to have based part of its claims against Kem Sokha on a video clip that shows the opposition leader giving a public speech in which he describes a grassroots political strategy to challenge Hun Sen with USA support.
Kem Sokha was taken away in handcuffs after a force of between 100 to 200 officers swept his home, according his daughter, Monovithya Kem, who is also a member of his embattled Cambodia National Rescue Party. "The above act of this secret conspiracy is treason", the government said in a statement. In recent years, he has become one of China's closest regional allies, and made increasingly strident verbal attacks on the European Union, the United Nations, and the US, as well as any global organizations that criticized him for violations of human or political rights.More news: Venezuela Slams Opposition's Statement Supporting Sanctions
More news: US Open 2017: Karolina Pliskova rolls in her first-round match
More news: US Missile Defense Test Hits and a Miss
Charles Santiago, a member of the Malaysian Parliament and chairman of the organization, said the arrest violated the immunity protection that should be afforded Mr. Kem Sokha as a member of Cambodia's Parliament.
The capture was made after Cambodia's police found a video broadcast by Cambodian Broadcasting Network (CBN) headquartered in Australia and other evidence showing Kem Sokha and his accomplices secretly conspired with foreigners to harm Cambodia. "This is a clear crime and there's no need to make further investigation because he has confessed already".
Mu Sochua, a vice-president of the opposition party, insisted that the charges had been fabricated.
"The arrest of Kem Sokha is a disastrous setback for Cambodia's human rights situation", said John Sifton, Asia advocacy director at Human Rights Watch.
Kem Sokha, 64, has led the main opposition CNRP since his predecessor, Sam Raimsy, resigned in February after party law amendments outlawed political parties led by people with criminal convictions.
Hun Sen, who has ruled Cambodia for more than three decades and has shown no signs of willingness to relinquish power, last month stepped up attacks on the media and non-governmental organizations. He now lives in exile.
"The government's charges lack credibility, given its long record of misusing its legal system to silence or intimidate critics and political opponents", Sifton said.