A woman has fallen into a three-metre sinkhole while hanging out washing at Springvale in Melbourne's outer east, emergency crews say.

The ground opened up under the 45-year-old woman just before midday on Tuesday on Olympic Avenue and she slid down the hole into a pool of water.

The woman told paramedics she could not touch the bottom of the hole and had to swim to keep afloat.

Paramedic Stephanie Palamberis said at one point the woman's head was under water.

The woman who fell into the sinkhole had to swim to stay afloat underground. ( ABC News )

"The woman told us she was hanging washing out in the backyard at about 11:30am when the ground gave way," she said.

"She fell with the dirt and mud, dropping about three metres and landing in waist deep water.

"The woman managed to attract attention of neighbours after about 30 minutes and emergency services were called."

Firefighters arrived on scene a short time later and pulled her from the hole.

Paramedics said she was not injured.

CFA operations officer Paul Carrigg said residents in the area were advised to stay indoors.

"This was a very unusual incident," he said.

"Fortunately the lady has escaped without injury though she was obviously shaken up.

"We have doorknocked all residents in the street and advised them to stay indoors until council engineers investigate further."