Sept 12 (Reuters) - Venezuela's PDVSA expects to reopen its main port's South dock by the end of September, easing strains on crude exports delayed due to a tanker collision last month, according to internal trade documents from the state-run oil firm seen by Reuters.

The South American country's crude exports have remained slow in recent weeks as few customers have accepted the 500,000-barrels-per-cargo maximum neighboring terminals can handle. (Reporting by Marianna Parraga Editing by Marguerita Choy)