Growth in the north should at least keep pace with the south over the next five years, he said.
Plans include upgrades to the M62 between Leeds and Manchester and the A1 in Yorkshire, and one million apprenticeships reported BBC.
Labour has said public services face “disintegration” due to Tory cuts.
Mr Cameron used a speech at the headquarters of Asda in Leeds to restate his party’s ambitions for a “northern powerhouse”, underpinned by devolution of economic, transport and care budgets to the north-west of England and new powers for Yorkshire.
He also visited the key marginal constituencies of Pudsey in West Yorkshire and Pendle in Lancashire, where the Conservatives are defending slim majorities against Labour.