Two hospitals spot-checked by new get-tough hygiene teams have been given five days to clean up their wards.
Inspectors took this picture inside Nevill Hall Hospital, Abergavenny
The emergency unit at Nevill Hall hospital in Abergavenny was said to be "cramped" and "dirty" while Morriston Hospital in Swansea also had problems.
Health Minister Edwina Hart announced the surprise checks on Tuesday as part of a cleanliness drive in hospitals.
Swansea and Gwent health trusts said they would address the hygiene failings identified in the inspections.
The checks were carried out by the independent watchdog Healthcare Inspectorate Wales (HIW).
Both trusts have been told to make action plans to address the findings of the spot checks by 31 October.
Inspectors found the "general environment" of the accident and emergency department at Nevill Hall to be "cramped, cluttered, dusty and shabby".
They said the toilets were clean but the staff toilets and changing areas were "untidy and dirty".
The inspectors also found that not all alcohol pumps, which are meant to help prevent MRSA infections, had gel solution in them.
In his letter to Gwent Healthcare NHS Trust, HIW chief executive Peter Higson also said inspectors had identified waste management issues.
"A used blood bag and line was found in a sink in the utility area of one ward," he wrote.
"The sink in the kitchen area of the acute medical ward had inappropriate taps and was obstructed by trolleys, making it difficult to access."
In a similar letter to Swansea NHS Trust, Mr Higson said that his inspectors could find no fault with the hospital's A and E unit.
Nevill Hall Hospital's cleanliness featured in newspaper articles
But they were concerned about food storage arrangements on the medical admissions ward and its kitchen which was found to be "dirty" and "unmaintained".
"We understand that recent changes to the purchasing arrangements at the trust have led to storage issues," Mr Higson wrote.
"The current situation needs to be addressed as a matter of urgency."
Earlier this week, the Western Mail published pictures of dirty walls and washbasins that it claimed were taken secretly in Nevill Hall hospital's accident and emergency department.
On Tuesday, retired university professor Clare Wenger also wrote a 4,700-word dossier criticising the dirty conditions she claims she found while a patient at Ysbyty Glan Clwyd, Bodwelwyddan.
Ms Hart said she had ordered Tuesday's spot checks after reading the media coverage of Nevill Hall and Ms Wenger with "dismay".