The management group, which is a government body responsible for conserving wildlife habitats, has said that developments in Wansbeck, Blyth and Seaton Sluice could have a "cumulative impact" on coastal habitats.

In response to a large public consultation on plans to build 300 homes, a new school and green public spaces on the former Bates Colliery site, Natural England has expressed concerns about its environmental impact.

Blyth Valley Council's strategic planning and regeneration manager Rob Horne said: "We've had 219 responses to the public consultation.

"A lot of these were concerned that the development is next to a Site of Special Scientific Interest (SSSI) and 'Special Protection Area'.

"Natural England has highlighted the cumulative impact that the whole of the development could have on the south east Northumberland coast.

"This is the first time the cumulative impact has been highlighted, rather than looking at the developments separately.

"The issues raised should help ensure developers enhance and protect these areas."

Mr Horne said that meetings with Natural England had been set up, and that a "co-operative spirit" would have to exist for their concerns to be considered in the development.

Since the consultation, Blyth Valley Borough Council planners have agreed to carry out an appropriate assessment of the whole estuary and shoreline development.

The 'master plan' aims to regenerate the estuary of the river Blyth and create a sustainable community with green spaces, cycle routes and integrated public transport borders, SSSIs, Special Protection Areas and a wetland.

These areas are home to internationally important numbers of sandpiper and turnstone, and nationally important sanderlings, ringed plover, redshank and golden plover.

Other shore birds include large numbers of curlews, dunlin, and lapwing.

Spokesman for Natural England, David Hirst, said: "We believe that the natural environment is a valuable asset both locally and nationally, that can enhance the appeal and value of new developments.

"We are delighted that our views have been welcomed by Blyth Valley Council, and this month Natural England has met with the local authority's officers along with SENNTRi.

"This has resulted in a greater understanding of environmental issues and a more strategic approach to help ensure that developments in the Blyth estuary area both protect and enhance the environmental assets including wildlife, with the creation of an environmental working group lead by SENNTRi."