A "bad dose of flu" has forced Conservative leader David Cameron to cancel a visit to meet first-time home-buyers in Leeds.
David Cameron became a father for the third time last month
Mr Cameron was to join TV presenter Kirstie Allsopp to unveil plans to help people onto the property ladder.
But it is understood the illness meant Mr Cameron, who recently became a father for the third time, stayed in London and did not travel north.
Frontbenchers Michael Gove and Caroline Spelman were due to launch the plan.
Ms Spelman, who shadows deputy prime minister John Prescott, said achieving wider home ownership was "a matter of social justice".
"We want to bring down the barriers to getting on the housing ladder, to share prosperity, to give families the scope to grow and to fulfil people's aspirations of having a home of their own," she said.
The key areas of the Tories' new five-point plan are:
- Ensuring more homes suitable for first-time buyers are built, while protecting the environment
- Making sure planning rules encourage the creation of homes with the gardens and parking spaces that families want
- Opening up shared-ownership schemes to more than just public sector workers
- Opposing the government's new home sellers' packs, which the Conservatives say are bureaucratic
- Making it easier for council house tenants to buy their own home, with part-ownership as a step along the way.
The Conservatives' plans were welcomed by the Home Builders Federation, whose executive chairman Stewart Baseley who said current regulations were "severely restricting choice and distorting the market".
"The HBF welcomes the Conservative Party's commitment to look at ambitious changes to planning regulations to help the market deliver the homes that people aspire to own," he said.
"House builders are best placed to respond to consumer demand for different types of home. To do this, we need a planning system that is efficient, predictable and, above all, responsive to market demand."