The South West was found to have the highest proportion of accessible coast
Hundreds of miles of the English coastline are inaccessible to the public, according to Natural England.
And miles of footpaths which provide public rights of way by the coast could vanish into the sea within 20 years because of coastal erosion, it warned.
Maps drawn up as part of plans for a coastal path around England showed 34% of the 2,478 miles (3,988km) of shore does not have full access for walkers.
On average, people can walk about two miles before finding their way blocked.
Natural England, which advises the government on the natural environment, is aiming to create a coastal path around the whole of England in a £50m scheme over the next decade.
ENGLAND'S COASTLINE ACCESS
Percentage of coastline with "satisfactory, legally secure path"
North East - 67%
North West - 44%
Yorkshire and The Humber - 70%
Lincolnshire - 61%
East of England - 68%
South East - 63%
South West - 76%
Source: Natural England
The path would have recreational space or "spreading room" around it, and is being created under the Marine and Coastal Access Bill, which is due to become law this autumn.
But an audit carried out before the process of creating the path begins has shown much of the coast is not fully accessible, including beaches people can only walk along at low tide, areas shut off by private landowners and pathways which are dangerous or do not have views of the sea.
A total of 921 miles (1,482km) of coastline was judged not to have "satisfactory, legal secure paths" with about half of that land considered completely inaccessible to the public, with no walked path at present.
The remainder has some kind of access, such as with the permission of a landowner, but is not legally secure and offers no guaranteed right of way.
One aim of the pathway scheme is to create walkways not at risk to erosion
The greatest provision of accessible shoreline is in the South West, where 76% was judged fully accessible, and the least is in the North West where just 44% is considered to have a satisfactory, legally secure path.
Paul Johnson, Natural England's coastal access policy manager, said the issue of erosion was central to the need to get the legislation passed.
He said: "At the moment the real problem is when a right of way falls into the sea, as it often does, effectively you lose it."
The Ramblers Association has welcomed the scheme with chief executive Tom Franklin urging the government to "hold firm and introduce legislation that will make access to our coast the envy of Europe and the world".
Some landowners have voiced concerns, fearing a public path being created through their property.
But the legislation now provides scope for appeals and Natural England has insisted the drawing up of the path will be done in full consultation with affected locals.