The father of Virginia shooting victim Alison Parker has urged Congress to defy the gun lobby and pass laws to strengthen background checks for firearm purchasers.

Andy Parker told a Capitol Hill rally that "we can, we must, and we will" prevail over opponents of new background check legislation, such as the National Rifle Association.

Mr Parker's daughter and WDBJ-TV cameraman Adam Ward were shot dead during a live television interview last month at a community outside Roanoke.

Mr Parker was joined at the rally by Virginia Governor Terry McAuliffe and the state's two senators.

They urged Congress to revisit a failed 2013 vote on legislation requiring background checks for online gun sales and purchases at gun shows.