OIL companies will be invited to bid annually for new batches of North Sea licences under a five-year programme to speed up exploration announced yesterday by the Department of Trade and Industry.

But award of new drilling areas in the Atlantic - where Greenpeace has been mounting protests - could be delayed at least until 2001 under the plans which wil1 apply new environmental regulations to future activities.

Despite this, a spokesman for the UK Offshore Operators Association welcomed the proposals which would mean more frequent allocations of licences in proven oil and gas exploration areas than the two-year intervals between previous rounds.

He said that companies had not previously been sure how the Labour Government would respond to the need for regular licensing rounds and would await with interest details of the areas offered in the first of the new rounds promised in the autumn.

But the industry has also been told that DTI officials will examine the extent to which companies have failed to draw up development plans within a six-year period for discoveries made under licences issued in previous rounds.

This has resulted in an estimated 400 suspended wellheads, mainly in the North Sea, which the DTI claimed caused seabed obstructions to the inconvenience and danger of other sea users.

"Officials are working on a review of fallow discoveries with licences to encourage companies to reconsider plans for them," the department said.

Details of the new areas open for licensing in all parts of the North Sea and the Morecambe and Liverpool Bay sections of the Irish Sea will be formally announced later this year in a notice in the Official Journal of the European Communities.

Companies will have 90 days to make applications which will be considered by the DTI for awards to be announced around Easter next year.

The timetable means that applications will have to be made before companies know of any changes planned in the oil taxation system as a result of a joint study by the DTI, Inland Revenue and the Treasury which could recommend measures for the Budget next spring.