* EU, Iceland in dispute over fish quotas
* Row threatens Iceland's bid to join EU
BRUSSELS, Jan 14 (Reuters) - The European Union will block landings of mackerel from Icelandic boats at EU ports in a dispute over fishing quotas, a European Commission spokesman said on Friday.
The Commission, the executive of the 27-member EU, formally notified the European Economic Area of the action, the final step before enforcing it.
"We have informed the EEA joint committee that we will implement the landing bans without further delay," commission spokesman Oliver Drewes told Reuters.
Iceland's decision to raise its mackerel fishing quotas last year has brought it into conflict with Britain, Ireland and Norway, threatening the island nation's bid to join the EU.
The EEA groups the EU's 27 members with Iceland, Norway and Liechtenstein.
It was not immediately clear how the ban would deal with issues such as ships carrying mixed catches or imports of processed fish.
Home to just 320,000 people but a major power in the Atlantic fisheries, Iceland began talks last year on joining the EU in the hope of greater stability and financial security after the collapse of its banking system in 2008.
But the island has also sought to benefit from a surge in mackerel stocks in its waters, an apparent consequence of warmer sea temperatures.
Talks broke down last summer and Iceland unilaterally increased the amount of mackerel its boats could catch to 130,000 tonnes, compared to a traditional catch which the EU estimates at 2,000 tonnes.
It has prompted comparisons with the 'cod wars' of the 1950s and 1970s, when Iceland and Britain deployed naval forces.
Iceland says more than 1 million tonnes of mackerel, a quarter of the stock, migrated into its economic zone during the five-month summer feeding season. It plans to maintain this year's 17 percent share of the north Atlantic catch in 2011.
It criticised the EU and Norway last month for failing to take that into account when they jointly decided to take 583,882 tonnes of mackerel in 2011, the majority of the amount that scientists say is ecologically safe to catch. (Reporting by Juliane von Reppert-Bismarck, Editing by Janet Lawrence)