OSLO, April 9 (Reuters) - Norway’s $1.3 trillion sovereign wealth fund, the world’s largest, should not include Saudi Arabian companies in the reference index governing the fund’s investment, the finance ministry said on Friday. Saudi stocks should not be included due to environmental, social and corporate governance (ESG) risk, the ministry said in its annual recommendation to parliament. The government rules in a minority and must win the support of other parties in parliament to pass its proposals.