The recently appointed enforcement chief of the Securities and Exchange Commission warned yesterday that the agency will monitor markets carefully for abuses during current economic difficulties.

"History tells us that times of economic turmoil spawn new abuses and deceptions," said John M. Fedders, who promised vigilance against those abuses. Fedders spoke to a meeting of the Association of General Counsels yesterday.

Fedders said the SEC will continue its stepped-up efforts against illegal profiteering through the use of insider information and won't hesitate to use strong circumstantial evidence to build those cases. The SEC currently is investigating heavy trading in options in the Santa Fe International Corp. shortly before the announcement of the company's takeover by the Kuwait government-controlled oil firm.

"We will carefully scrutinize trading activity preceding public announcement of such transaction," Fedders said. Fedders noted that the SEC has brought more than 40 cases of insider trading abuses since January 1978, which he said is more than the total of such cases brought between 1934 and 1978.

Fedders said the agency also will go after abuses and manipulation in the "hot issue" centered in Denver where highly speculative stocks are traded and will increase its monitoring of corporate disclosure.

Fedders warned the group that the SEC will punish attempts to interfere with investigations and will also seek sanctions against corporations that file groundless lawsuits against the SEC enforcement staff in an attempt to impede investigations.