The number of new mothers attempting to breastfeed has fallen in England for the first time in almost a decade.

New figures suggest that 5,700 fewer women initiated breastfeeding with their child in 2012-13 than the year before. It is the first recorded fall since the Department of Health began collecting and releasing the statistics in 2004.

The figures also show that in 2012-13, 327,048 women were not breastfeeding their baby at all by the time of their six- or eight-week checkups – just under half of all maternities. The DoH recommends that mothers exclusively breastfeed their children for the first six months of their lives.

The statistics have prompted the Royal College of Midwives (RCM) to voice serious concerns over a lack of promotion of breastfeeding under the current government. In 2011 the coalition scrapped funding for National Breastfeeding Awareness Week, which has been promoting the acceptance of breastfeeding since 1993. The RCM also says there is a shortage of 5,000 midwives and reports that the NHS is cutting back on antenatal and postnatal care as its budget is squeezed. It also laments the scrapping of infant feeding co-ordinators, who had been encouraging breastfeeding in those parts of the country with the lowest uptake.

The figures provide evidence of some startling regional variations. In areas with high levels of social deprivation – such as Knowsley, Hartlepool and North East Lincolnshire – four in five mothers are not breastfeeding at all some six to eight weeks after their child's birth. By contrast, in Kensington, west London, 87% of mothers said they were partially or totally breastfeeding at the same stage.

Louise Silverton, the RCM's director of midwifery, writing on this newspaper's website, said: "Breastfeeding is no longer a public health issue. Under the previous government, there was a 10-year infant feeding strategy, but there is no such foundation and framework in place now.

"There is now a lack of health promotion about breastfeeding. There is no longer a national breastfeeding co-ordinator to co-ordinate the country's strategy or a national strategy, while Wales and Scotland have strategies. Indeed, this government is 'hands off' regarding breastfeeding."

The dip in numbers is small in relation to the 670,535 births recorded in England last year. However, the figures suggest that a gradual rise in both the initiation of breastfeeding and its prevalence weeks later is stalling. The proportion of women initiating breastfeeding – when a mother either puts her baby to the breast within 48 hours of birth or the baby is given any of the mother's breast milk – had been rising by about one percentage point a year between 2004 and 2010-11.

Diane Abbott, the shadow public health minister, said the coalition was failing mothers and babies and needed to act. "Jeremy Hunt should explain to families why the government has axed the annual week promoting breastfeeding and why the Department of Health advisory committee on breastfeeding no longer meets," she said. "The strain the government has put on our NHS means we're now seeing overstretched midwives and health visitors struggling to maintain breastfeeding levels among new mums.

"I think we'll end up with a situation where young mothers see expensive television ads every evening for milk formula, but no such promotion for the benefits of breastfeeding."

Dan Poulter, the health services minister, said despite the recent dip, figures had risen since 2010 and the government was working to promote breastfeeding benefits. "We have pledged to increase the number of health visitors by 4,200 by 2015, and there are now over 1,000 more since May 2010. We have also increased the number of midwives by nearly 1,400," he said.

Last year Unicef UK published research claiming the NHS could save £40m a year if more women were given help to breastfeed for longer. It said there were potential savings in five disease areas: breast cancer in mothers, gastroenteritis, respiratory illness, ear infections and the life-threatening condition necrotising enterocolitis in babies.