Cambodian police have arrested and deported 160 Christians who crossed the border illegally to escape violence in their country last week.
The Christians are members of a Vietnamese ethnic minority known as the Montagnards.
An estimated 400 Christians were killed during peaceful and prayerful demonstrations in the Central Highlands of Vietnam over the Easter period. Thousands of Montagnards took part in the protests.
It was feared at the time that the incident might spark a refugee movement, with people heading for the Cambodian border. The Cambodians had however closed the border to refugees. Three years ago, police crushed similar demonstrations in the area, prompting a mass exodus to Cambodia.
Now, unidentified human rights workers stationed on the border in north-eastern Cambodia have said they have received reports that police arrested 100 Christian tribes people in Mondulkiri province on April 12, and another 60 two days later, The Cambodia Daily reports.
"It is a lie," Mondulkiri police chief, Reach Samnang, told the newspaper. "It's not true. We have nothing to hide."
Police were not immediately available to comment on the report, and a call by The Associated Press to the U.N. refugee agency in Phnom Penh was not immediately returned. The United Nations High Commissioner for Refugees is responsible for administering illegal migrants.
In an oral statement to the United Nations Human Rights Commission in Geneva last year, a Christian campaign group highlighted the dangers to Christians.
The Commission was informed by the Jubilee Campaign that in Vietnam, the indigenous Degar people of the Central Highlands, face intense and systematic human rights abuses from the Vietnamese authorities including extrajudicial executions and anti-Christian persecution.
Police haven't caught all the Montagnards who entered Cambodia, the unidentified rights workers told the newspaper.
"Vietnamese soldiers and police are travelling freely on Cambodian soil, hunting for those people," one of the workers said.