A cross-party inquiry by MPs and peers said the Equalities and Human Rights Commission (EHRC) had "neglected its responsibilities" in the area.
But it also lashed out at political parties for failing to deal with a "culture of silence" that prevented victims speaking out and a lack of training to deal with the "ruthless nature" of campaigning. And it called for cross-party agreement on a system for reporting discrimination claims to be investigated to a set timetable, with findings published.
Among cases examined by the inquiry - chaired by Labour MP Natascha Engel - were death threats made against Tory MP Lee Scott which left him seeking police escorts during the 2010 campaign, and a pig's head found by the children of ex-Labour minister Parmjit Dhanda outside his home.
It concluded that while the law needed modernising, "the biggest gap in the system is a statutory body willing to lead the charge against discrimination".
The panel said it was "very disappointed" the issue was not considered a priority by the EHRC.