Are they a substitute for government regulation or do they complement it?

Corporate social obligation (CSR) advances a dream of business responsibility to an extensive variety of partners, other than shareholders and speculators. Key territories of concern are ecological security and the wellbeing of representatives, the group and common society when all is said in done, both now and later on. 
​Do you think corporate codes of conduct can have an effect on making firms more socially responsible? Are they a substitute for government regulation or do they complement it?