The coalition government has pledged to end most mixed sex hospital accommodation in England.
It says tens of thousands of patients are still being placed in mixed sex wards or bays every year without clinical justification.
Labour committed to the policy when it won power in 1997, but failed to abolish them completely.
Health Secretary Andrew Lansley said he was determined to end the practice and will introduce new NHS sanctions.
The move will apply to all wards except intensive care and A&E.
It would mean patients sharing sleeping, bathroom and toilet facilities only with people of the same sex. This could be through single rooms or whole wards occupied by men or women only, or mixed wards in which men and women are separated in bays or rooms.
Announcing the new measures, the Department of Health said it had new data suggesting tens of thousands of patients are still being placed in mixed sex accommodation every year "without clinical justification".
From January, routine reporting of such "breaches" will be introduced, and the data will be made public.
Hospitals will face fines if they do not meet the standards.
Mr Lansley said: "Patients should not suffer the indignity of being cared for in mixed sex accommodation. I am determined to put an end to this practice, where it is not clinically justified.
"In the future, NHS organisations will have clear standards, spelling out when they should report a breach.
"Where NHS organisations fail to meet this standard, we will let the public know that they have failed and we will strengthen the fines which may apply.
"Patients and members of the public will be able to see which services continue to allow patients to suffer the indignity of mixed sex accommodation."
Katherine Murphy, Chief Executive of the Patients Association, said the group welcomed an end to mixed sex wards but had concerns about the proposed timeline.
She said: "Each incoming secretary of state has made exactly this same pledge since 1997, and with the NHS facing financial restrictions as part of the Government's austerity drive, we remain sceptical that this rhetoric will become reality.
"In light of budget cuts, there are potentially huge implications for patients, such as increases in waiting times as patients wait for a bed on a single sex ward.
"Patients should not have to choose between death and dignity."
Janet Davies of the Royal College of Nursing said some hospitals were already having problems with balancing the books. Adding extra financial pressure could make them look at making cuts elsewhere, which may impact on care, she said.
"The challenge now is likely to be mainly in older hospitals where wards were built for a different era of healthcare," she said.
It is accepted that throughout the UK there will be instances where providing single-sex accommodation is not the priority, such as in the emergency care setting.
Northern Ireland says it is working to abolish mixed-sex accommodation and has pledged that all new hospitals built will have this aim in mind.
In Scotland, mixed-sex wards were abolished in 2005.
In Wales, 95% of all hospital accommodation is in single sex wards or single rooms, and this is expected to reach 100% by the end of March 2011.