One of the ancient stones from Jerusalem's Western Wall has dislodged and crashed into an adjacent prayer area, miraculously missing a woman who was praying just metres away.

Footage shows the block plummeting and landing on a raised wooded platform used for egalitarian prayer.

The 100 kilogram stone narrowly missed a woman praying nearby.

“I didn’t hear or feel anything until landed right next to my feet and there is a big hole in the floor as you can see, the deck, the boards of the stairs were even broken,” she told the BBC.

“I didn’t understand where it came from, I looked up and everything was intact.”

Western Wall Rabbi Shmuel Rabinovich said it was a highly unusual event, and he hadn't seen anything like it in decades. He says moisture or plant growth could have dislodged the stone.

The Western Wall, a remnant of the compound where the biblical Jewish temples once stood, is the holiest site where Jews can pray.

Jews marked Sunday the Tisha B'Av fast commemorating the temples' destruction.

Jerusalem Mayor Nir Barkat said it's "a great miracle" that the 100kg stone landed near a worshipper and did not harm her.

The area was closed for maintenance.