ATTAPEU, Laos — As heavy rains lashed southern Laos over the weekend, volunteers from many countries were continuing to help victims of earlier flooding caused by the failure of a foreign-funded hydropower dam.

“It shows the spirit of humanity,” Yen Saisamon, a 17-year-old Laotian volunteer, said on Friday at a relief center in the town of Attapeu, where cardboard boxes of instant noodles and condiments were labeled in Chinese, Thai and Vietnamese.

Yet if foreigners are helping now, they also share a piece of the blame.

The accident at the billion-dollar Xe-Pian Xe-Namnoy hydroelectric project last week has cast a harsh spotlight on the unspoken compact between the ruling Lao People’s Revolutionary Party and giant outside financial interests: The companies get access to Lao’s abundant natural resources; Laotian officials get some revenue; and no one will cast undue scrutiny on investment projects that exacerbate rural poverty — or, in this case, kill innocent villagers.

Laos’s one-party communist government and the international financial institutions that support it have long embraced a “high-wire act” of prioritizing investment over stronger regulation, said Keith Barney, an expert on Laos at the Australian National University. But in the accident’s wake, “the potential pitfalls of poor regulation are now evident for everyone to see,” he said.