Chief Election Commissioner V S Sampath told reporters that the issue of money power was a "challenge."
"Money (power) is a serious issue in Karnataka. It is a challenge. Strict action will be taken to keep it under check," Sampath, who is on a private visit here, said.
Single-phase polls to Karnataka Assembly will be held on May 5 with the ruling BJP, Opposition Congress and JD(S) and former Chief Minister B S Yeddyurappa's KJP, among others, in the fray.