According to Komtar assemblyperson Ng Wei Aik, he was alerted about the attack on the three-storey building at about 4am by a security volunteer.
"We are under attack again! Wisma DAP Pg been splashed with 5 packs of red paints early this morning," Ng, the state DAP Youth chief, announced on Twitter.
Ng, when contacted, told Malaysiakini through SMS that he would be lodging a police report at the Jalan Pattani Northeast District police station later this morning.
The building, which cost the party about RM3 million, was launched early this year.
It is also learnt that the Air Putih service centre in Penang Chief Minister Lim Guan Eng's state seat was also splashed with red paint.
A party member was said to have discovered the incident at about 6am.
This is the third attack against the party's headquarters since last year. On Aug 14, 2011, the building - previously located on Jalan Talipon - was splashed with orange and red paint.
At the same time, Ng's service centre in Lorong Seratus Tahun was also hit with both orange and red paint (left). A car parked outside the service centre that day was found smeared with paint.
According to eye-witnesses, a group of six on three motorcycles had come to Ng's service centre at around 1.20am and hurled a number of small plastic bags with paint.
Arson attempt in second attack
Another attack, which occurred four days later, was more serious.
It involved suspected arson, where a stack of newspapers outside the building was set on fire at about 3am.
Ng, who is also political secretary to the Penang CM, told the media the fire was put out by neighbouring residents and the Fire Department 20 minutes and this had stopped the flames from spreading to other parts of the building.
In both cases, police was alerted but they have yet to find the culprits.
In the case of arson, then Penang police chief Ayub Yaacob had visited the DAP building and vowed a thorough investigation into the incident.