By Kham Nguyen

HANOI, Sept 29 (Reuters) - A Vietnam court sentenced to death a former chairman of state -run PetroVietnam on Friday after finding him guilty in the mass trial of 51 officials and bankers accused of graft and mismanagement that led to losses of $69 million.

The ex-PetroVietnam chairman Nguyen Xuan Son was the second of the accused to be sentenced as the People's Court of Hanoi began delivering its verdict in the long running trial.

The court had earlier in the day sentenced tycoon Ha Van Tham, founder of Ocean Group's banking unit, Ocean Bank, to life imprisonment, having found him guilty of charges ranging from embezzlement to abuse of power.

Dozens of other banking and energy officials were also sentenced to jail terms.

The mass trial is a result of the tougher stance on corruption taken by the ruling Communist Party since Vietnam's security establishment emerged stronger from a power struggle last year in which ex-Prime Minister Nguyen Tan Dung lost out. (Additional reporting and writing by Mi Nguyen; Editing by Simon Cameron-Moore)