The new minister for regional revitalization has said he won't resign over reports that he tried to obstruct an investigation by the securities watchdog.

Kozo Yamamoto, 68, who took the post a month ago, denied magazine reports that he exerted pressure on the Securities and Exchange Surveillance Commission during an insider trading case in 2012 that involved an acquaintance.

"I didn't mean to put pressure on the investigation at all," Yamamoto, an economic adviser to Prime Minister Shinzo Abe, said in a statement Thursday.