The report, carried out by Cardiff Business School and the Welsh Institute of Rural Studies at Aberystwyth University, highlights the fragile state of the Pembrokeshire economy prior to February's tanker disaster.
The gross domestic product of the area was already 72% of the UK average. The loss of more than 70,000 tonnes of crude oil into the sea cut almost £21m from tourism spending alone in 1996, the report reveals.
'The figure represents a substantial impact, particularly in the context of a Pembrokeshire tourism spend of around £160m and an estimated local GDP of just under £800m' it states.
'We will be seeking meetings with the secretary of state for Wales and the European Commission to attract more government commitment and European Structural Funds to redress the problems we are now facing', he said.
Long-term priorities include improvements to local trunk roads and the diversification of regional activity.
The council has so far spent more than £4m on the oil clean-up operation, of which its insurers had repaid £360,000 by the beginning of last month.