Trams on a number of lines running through Melbourne's CBD have resumed after earlier being brought to a standstill due to a power fault.

Services running along Bourke, La Trobe and William streets have resumed, Yarra Trams tweeted at 4.15pm.

An aerial shot of the stopped trams Credit:Nine News

But commuters are warned that delays will continue as trams return to their normal frequency.

The power failure shut down trams in the heart of the city for more than an hour.