Speaking today at the Institute of Economic Development’s annual conference in London, Cable said that the housing "problem is one that is really disastrous and getting worse", pointing to "completely unsustainable levels of affordability".
Cable, the former Liberal Democrat MP for Twickenham, told the conference, organised in association with Planning, that while "restrictive" planning rules have recently been relaxed, politicians are "simply unwilling to grasp a lot of the really tricky issues".
He said that these included "confronting people in rural areas with the need to develop new towns and villages", as well as "opening up the issue of the green belt".
Cable told the conference that he does not believe that the green belt should be "trashed or abandoned", but he added that some flexibility should be exercised within it, "which is currently not even on the table".
Cable said: "You have all of these supply problems which are making it extraordinarily difficult to get up to even credible levels of numbers."
He added: "It’s very difficult to see how the supply problems can be overcome without activist government.
"Unless councils are given the powers to borrow and build, unless central government is willing to intervene in order to create new town developments … the supply will simply not materialise.
"And I fear we are drifting into a position in which none of these key issues are properly addressed."