"We won't stop normal people coming in and out, we only stop rebels", national police spokesman Chhay Kim Khoeun told Reuters.
After his arrival in Kuala Lumpur on Saturday, MP Nurul Izzah invited Rainsy to a meeting in Malaysian parliament on Tuesday, but it is not known if he has accepted.
A co-founder of the court-disbanded Cambodia National Rescue Party (CNRP), Rainsy had vowed to re-enter Cambodia on Saturday - nearly four years after fleeing overseas to evade arrest in a case widely seen as politically motivated.
The saga of Sam Rainsy's return also elicited a response by U.S. Senator Ed Markey, who tweeted on Thursday that Hun Sen had "undermined democracy and rights" in Cambodia and demanded that he allow CNRP leaders to return over the weekend, adding that he had introduced to Congress a bipartisan resolution calling for their peaceful repatriation "so he knows we're watching".
"Keep up the hope". The country's human rights commission said Sochua and two other Cambodian activists arrested in Malaysia this week as they sought to fly to Thailand have since been released.
A Cambodian court subsequently charged Sam Rainsy and the eight other party figures with plotting a coup.
Mr Rainsy fled to Paris in 2015 after a conviction for criminal defamation and faces a five-year sentence in a separate case. He says the charges were politically motivated. Thai Prime Minister Prayuth Chan-ocha earlier said he would be barred from entering.
"But the Royal Government of Cambodia has also announced the right to take legal action against any actions that attempt to undermine peace, social stability and security of the state".
Saifuddin said the authorities had allowed the Cambodian opposition leaders to enter this country because the Malaysian government made decisions without any pressure from any quarter.
An opposition official in Thailand said plans to return on Saturday were abandoned.
Pheng Heng, a lawyer for Kem Sokha, confirmed that some restrictions were lifted but said the ban on politics was too broadly worded and unclear.
"You can see the intimidation, the harassment, the crackdown, the arrests".
"This is just another cynical move by Hun Sen to try and hoodwink the worldwide community into thinking he is lifting his grip on the political opposition and should be seen for what it is", he said in a statement. Rainsy will give a speech to Malaysian parliament on November 12, he said.
"I want to go back to my home country", he said, while declining to say how he plans to do so.
On the day of his arrest, Cambodia Daily published its last edition with the image of the arrested politician on its front page, with "Descent Into Outright Dictatorship" written on top. The EU has threatened to strip the country of its EBA status citing alleged human rights breaches. "More governments in ASEAN need to emulate Malaysia if the bloc is ever going to rid itself of its reputation as a rights abusing club of recalcitrant dictators".
Speaking to RFA, CNRP deputy president Eng Chhai Eang said that the statements from Sok Ey San and Cambodia's mission in Geneva suggested that the CPP has no intention of initiating dialogue with the opposition, as urged by the US and United Nations, but he said that the CNRP will not abandon its goals.
The social gathering's dissolution was discovered as a political ploy to make sure victory by Hun Sen's event within the 2018 primary election by decreasing the one credible opposition group.