SEOUL (Reuters) - South Korea's police are investigating what some suspect could be a hacking attack on the country's major broadcasters and a large bank, they said on Wednesday.

Four major broadcasters were affected as well as Shinhan Bank, Part of Shinhan Financial Group, a major financial institution, the police and government said.

Initial speculation centered on a potential hacking attack by North Korea, which has hacked South Korean institutions before, but the police and South Korean government said they could not ascertain the cause of the outages.

(Reporting by Ju-min Park and Joyce Lee; Writing by Se Young Lee; Editing by David Chance)