The majority of the complaints were about companies from the property, retail and finance sectors, Minister for Communications and Information Yaacob Ibrahim said.
However, most of these companies broke the rules because they did not fully understand how to comply with them, and most were simply issued with advisory notices and warnings, Yaacob said.
Complaint numbers fell by 50% in 2015 as an education programme about the Act began to reach companies and the public, he said.
Two organisations were prosecuted under the rules. Star Zest Home Tuition and Huttons Asia continued to send multiple, unsolicited telemarketing messages to numbers that werelisted on the DNC register after being asked to stop by the PDPC, Yaacob said.
The PDPC also received around 26,500 complaints about messages relating to illegal activity including unlicensed money lending and illegal gambling. These were referred to the police, the minister said.
Data protection law expert Bryan Tan of Pinsent Masons, the law firm behind Out-Law.com said: "The numbers, though large, show a trend of awareness, at least for the DNC obligations. I note that the numbers relating to illegal activity is three times as large, lending credence to the concern that spam facilitates illegal activity."