The giant Hoa Binh and Son La power plants have water levels that are three to five meters higher than normal.
Pham Hong Phuong, EVN’s deputy director, said that this is the first time the dams are releasing water before the arrival of the flood season.
In previous years they only used to release water when full.
Rainfall in the north is set to exceed the average of recent years by 15-30 percent between July and October, according to the National Centre for Hydro - Meteorological Forecasting.
EVN anticipates a shortage of 1,500-2,400 megawatts during peak hours or periods of "extreme weather conditions" in the region as hydropower accounts for over 45 percent of power supply in this region.
The early water release is set to worsen things for EVN, which is already struggling with the surging costs of coal required for its thermal power plants.
Coal prices are 3.5 times the estimates it made earlier this year.
"Because of this, EVN is recording heavy losses, and water resources need to be utilized to ensure financial stability for EVN and the provinces of Son La and Hoa Binh," the utility said in a statement.
Phuong said that the two dams should gradually stop the release and retain water for electricity.
But Minister of Agriculture and Rural Development Le Minh Hoan said the hydropower plants are not only responsible for electricity supply, and also need to supply water and prevent flooding.
"I do not see EVN as a company that operates only for revenues and profits. Because EVN is a national asset, it needs to cooperate with [other government bodies] to protect the assets and lives of people."
He added that the release of water from the hydropower dams is based on correct protocols as water flows from China are rising.