A female worker provided the power tools used by two escaped inmates to carry out their daring prison break, a New York prosecutor says.

Joyce Mitchell, who befriended the two inmates, "provided some form of equipment or tools" to the two convicted murderers who busted out of the maximum security prison six days ago, Andrew Wylie, Clinton County District Attorney, told CNN.

US media had reported that the married woman may have been seduced by Richard Matt, and allegedly agreed to pick the two escapees up with a car, before changing her mind and being admitted to hospital with a panic attack.

The woman has been charged with providing material support for the men. Her husband and prison co-worker is also under investigation.

An exhaustive manhunt has been launched for the men - Matt and David Sweat - whose daring escape has been likened to Hollywood movies such as The Shawshank Redemption or Escape from Alcatraz.

More than 500 officers have been combing a thickly wooded area east of Dannemora, New York in search of the men.

Aiding in the manhunt are prison guards, forest rangers, FBI agents, federal marshals and border officers, K-9 units and helicopters.

Schools in the area, including in the village of Dannemora, are closed, as is a portion of the state highway.

There is a $US100,000 reward for information leading to their arrest.