The chancellor has promised "a significant economic policy response" in the event of a no-deal Brexit.
Sajid Javid did not give details, but the BBC's Norman Smith said it could mean tax cuts and reduced interest rates to help mitigate the impact.
Mr Javid is setting out plans for infrastructure investment on the second day of the Tory conference. But the event has so far been overshadowed by claims Boris Johnson touched a female journalist's thigh.