Six years after Canberrans were first consulted about possible light-rail routes between Civic and Woden, there remains no clear option that satisfies all parties.

The long-awaited light-rail link between Civic and Woden has hit a new roadblock after a senior federal official conceded that heritage values may block the existing proposals.

Six years after Canberrans were first consulted about possible routes, planners still lack an option that satisfies both the ACT government and the National Capital Authority (NCA), which controls the parliamentary area that light rail must travel through.