Services for sick and premature babies are being stretched to the limit, according to a leading charity.
Campaigners want more staff
Bliss said the majority of the neonatal units who replied to its survey were operating at or below half their minimum staffing levels.
It said that on average, every unit was forced to "close its doors" to new patients for a fortnight over a six month period.
The Department of Health said extra nurses had already been recruited.
The Bliss report found no improvements following similar surveys in 2006 and 2005 - and its chief executive, Andy Cole, said the service was "on the brink of collapse".
"We are concerned that the government still gives less priority to intensive care for babies than for adults and children," he said.
"The Department of Health's recent commitment to provide extra midwives is a step in the right direction for maternity services - we now need to see the same commitment to ensuring that there are adequate numbers of trained neonatal nurses for those babies born sick or premature."
A total of 195 neonatal units responded to the survey, issued using the Freedom of Information Act.
It found that many units were operating with bed occupancy well above those recommended by experts.
One in eight of the most specialist units in neonatal care reported average bed occupancy of 100% or more for an entire year.
Many parents have complained that a shortage of neonatal cots at their local hospital has meant long journeys for their babies.
The survey suggested that 10% of units were forced to refuse new admissions for two months or more out of six, and that, when the closures were averaged between all the units, it added up to two weeks out of six months for all of them.
Bliss estimates that, to meet recommendations, a further 2,600 trained neonatal nurses would be required across the UK - an increase of 37%. It predicts that, on current trends, with an increase in premature births, the situation would worsen.
Professor Neil Marlow, the president of the British Association of Perinatal Medicine, supported the findings of the report, and said that recent NHS reorganisations had held back vital improvements.
He said: "There is no reason why we shouldn't have absolutely the best neonatal intensive care service in the world.
"There should be enough money to do this, and there should be enough willingness.
"However, this is one of the only areas not covered by NHS targets, and things have not improved, and pressures are increasing over the years."
However, the Department of Health said that it was taking steps to improve recruitment, and said the issue would form part of the review conducted by new health minister Lord Darzi.
Ann Keen, another health minister, said: "We agree that it is important that neonatal units are staffed by trained, experienced nurses.
"That is why we are increasing the numbers of nurses in neonatal care - the number of paediatric nurses increased by 3,293 - 21.5% - between 1997 and September 2006.
"This growth is set to continue with the number of students doing children's nurse training increasing by 46.5%, or 654 students, in the same period."
Tina Pollard, chair of the Neonatal Nurses Association, said that it wholeheartedly supported the report findings.
"What Bliss have done is painted a very accurate picture of what is actually happening in neonatal units. There are genuine problems that need to be addressed, and things are not getting better."