The intruder was detected after he was spotted peering through a window, one floor above the hotel ballroom where the proceedings were taking place.
Following this, a group of security personnel rushed up to confront him, only to find out that he had locked himself in another room and refused to reveal himself.
Hotel staff managed to unlock the door later and after some hesitation, the intruder admitted that he was an undercover police personnel.
Security personnel managed to seize the intruder's tape recorder (see photo) and eight audio tapes.
'Perak is a police state'
At a hastily arranged press conference later, Perak DAP chief Ngeh Khoo Ham criticised the police for intruding a private function.
"Perak has become a police state and every law abiding citizen has to live in fear of intimation and harassment from law enforcement officers," he said.
Ngeh said he believed that many DAP leaders also have their mobile phones tapped, and this was another intrusion of privacy by the police.
He added that the party took extra security measures in view of the arson and vandalism attacks against several churches across the country.
At about 6.30pm, Ngeh and security personnel lodged a police report against the intrusion.
seals: wah .... to such extend ?