Jeremy Hunt will accuse hospitals on Friday of endangering patients' lives by "coasting" – meeting key targets but never striving to provide the highest-quality care because of ingrained complacency.

In a fresh attack on the NHS after last month's damning Francis report into the Mid Staffordshire hospital scandal, the health secretary will warn the service's leaders that simply delivering minimum standards is not enough.

"Coasting can kill. Not straight away, but over time as complacency sets in, organisations look inwards, standards drop and then suddenly, something gives," Hunt will say in a speech to a conference organised by the Nuffield Trust health thinktank to debate the future of healthcare.

"The lesson of Mid Staffs is surely that we need to understand why they fail in the first place, which means tackling mediocrity and low expectations before they turn into failure and tragedy."

Labour defended the NHS. "It's no good for ministers to blame hospitals and staff when it is they who have thrown the whole system into chaos with a huge reorganisation, which has siphoned £3bn out of frontline care," said Andy Burnham, the shadow health secretary.

"That is why so many hospitals do not have adequate staffing levels, as identified by the Care Quality Commission. Ministers need to start supporting the frontline and stop denigrating dedicated staff who are doing their best in the impossible circumstances created by this government."

The leader of Britain's nurses said frontline NHS staff were being hampered by a lack of resources, not ambition.

Speaking on BBC Radio 3's Today programme, Dr Peter Carter, chief executive and general secretary of the Royal College of Nursing, said: "Our members will agree that all hospitals should be aiming for excellence, but this requires investment and leadership.

"Frontline staff want to work in excellent hospitals, but they need the proper support to be able to do this. Team GB's fantastic success is down to a combination of ambition supported by proper investment and resources, and this needs to be emulated in the NHS," he said.

Mike Farrar, chief executive of the NHS Confederation, said hospitals needed to provide more information about the performance of the services they provide and had a crucial opportunity to undertake a "culture change", like that recommended by Francis.