A sinkhole opened up on Collins Street overnight, stopping eastbound traffic from Queen Street and exposing tree roots and pipes below.

City of Melbourne has confirmed that the hole, which is around one cubic metre, was caused by a crack in a barrel drain running under the busy CBD street.

The area has been cordoned off while crews repair the hole. The street is expected to reopen tomorrow.

Trams are still running in both directions and westbound traffic remains unaffected.

Follow Vic Traffic on Twitter for updates.