(Recasts first sentence with strategy behind proposal, adds detail on rules)
RIO DE JANEIRO, July 18 (Reuters) - Brazil's oil regulator is proposing a plan to allow companies to apply more flexible local content rules to pre-existing contracts, the agency chief said on Tuesday, in a bid to attract fresh investment by foreign oil majors into Latin America's top economy.
Decio Oddone, director of oil regulator ANP, said the agency would open a 30-day comment period on the proposal, followed by a hearing and publication of the rule in September.
In February, ANP sharply reduced local content requirements in future oil exploration and production contracts. It was a boon to oil companies that had complained of high costs but it enraged local suppliers.
If approved, the plan announced on Tuesday would extend the more flexible rules to new contracts going forward. (Reporting by Marta Nogueira and Alexandra Alper; Editing by Chizu Nomiyama and Matthew Lewis)