Shadow health secretary Andrew Lansley has hinted that a Conservative government could spend more on the NHS than a Labour government under Gordon Brown.
He said higher health spending - especially on public health - could also help improve the nation's economy.
Mr Lansley reminded delegates that Labour planned to slow the rise in health spending from 2008. But he said this might change under the Conservatives.
'I'm not going to tell you the NHS is going to have no more money in future,' he told delegates at a fringe meeting on Monday. 'I can't tell you because [shadow chancellor] George Osborne will not let me say how much that is.
'But what he's talking about is sharing the proceeds of growth between increased spending on public services and a reduction in tax.
'There is going to be demographic change, new clinical treatments and the development of new drugs which we will have to pay for as a tax-funded NHS.'
He said richer countries tended to spend more as a proportion of GDP on health: and the US had not suffered for spending more than the UK.
'It is not true to say that if we commit more to healthcare it will drag us down,' he said. 'Healthy countries are more economically successful. Healthcare is adding value and will help us increase productivity.'
He also reiterated his party's support for a tax-funded NHS rather than a social insurance system.