Staten Island DA Dan Donovan yesterday said he was launching an investigation of the state Independence Party following a report in The Post that the party chairman’s wife solicited a $10,000 business loan from a candidate who was seeking the party’s backing.

The disclosure came in a letter Donovan wrote in his other role, as a candidate for state attorney general, notifying Independence chairman Frank MacKay that he no longer wanted the party’s endorsement.

Tuesday, The Post reported that John Tabacco, who was running a in special election for City Council seat in 2009, was solicited for a $10,000 loan by MacKay’s wife, Kristin, on behalf of a computer company she co-founded.

“I applaud DA Donovan on his proactive move to demonstrate . . . that the leadership of the Independence Party has made its line toxic,” Tabacco said.

MacKay did not respond to a request for comment yesterday.