The huge NHS budget could be spent more efficiently, Mr Lansley says
The Conservatives are promising a large rise in the number of single rooms in NHS hospitals to help tackle infections and improve patient experiences.
All expectant mothers will be offered a single room if they want one, as will patients on mental health wards, health spokesman Andrew Lansley has announced.
The plan to create 45,000 extra single rooms by the end of the first term of a Tory government will cost about £1.5bn.
Opposition parties said it was unclear how the plan would be funded.
In his speech to the Conservatives' annual conference in Birmingham, Mr Lansley said Labour had failed to meet targets on providing more single rooms in new hospitals and increasing single-sex accommodation across the NHS.
He added: "No-one should be forced to suffer the indignity of staying on a mixed sex ward."
Under the Tory plans, the number of rooms set aside for treating people with hospital-acquired infections will be increased by 7%.
In a further guarantee, all patients admitted for planned care - excluding children - will have the option of having a single room.
The Tories estimate that about 93,200 single room beds will be needed, up from the 48,000 now available.
On the basis of recent and existing schemes to create single hospital rooms, the party believes the project will require annual expenditure of £314m over five years.
"By giving NHS patients the choice of a single room when they book their operation, we will ensure that they will be treated with the dignity they deserve," Mr Lansley added.
"Any stay in a hospital is a traumatic and trying time. We hope that the proposals we are announcing will make a big difference in removing unnecessary stress for patients and their families."
The Tories are trying to gain political ground on the NHS, long regarded as a core Labour issue, by accusing the government of wasting billions of pounds on bureaucracy and letting patients down.
In his speech, Mr Lansley also outlined plans to give more choice to patients and more powers to health professionals.
Focusing on treatment outcomes rather than central targets would mean money was better spent.
At a Tory conference fringe meeting on Sunday, frontbench spokesman Oliver Letwin said a free NHS remained a "treasured principle" but that patients should have more choice of providers within the health service.
Labour's Health Minister, Dawn Primarolo MP, said the Tories had not thought about how they would fund their health policies and were not focusing on what was best for patients.
She said: "Their plans to make it harder for people to see their GP in the evenings and at weekends show that the Tories still aren't on the side of patients."
The Liberal Democrats said the Tories were offering "nothing new" and would make the NHS less accountable to those paying for it.
The Royal College of Nursing welcomed the Tories' aim to cut nurses' paperwork and their pursuit of alternatives to mixed-sexed wards but said it would like to see more details of their "ambitious pledges".