Environmental concerns have been raised after a 'monster' supertrawler ship was spotted off the south coast of England.

The Lithuanian-registered Margiris fishing boat - once considered the second largest in the world - was banned from fishing in Australian waters in 2013.

Now the controversial boat, which has a deadweight of 6,200 tonnes, has been spotted off the coast of Sussex and Portsmouth over the last few days, according to MarineTraffic.

The giant supertrawler Margiris is seen here fishing just 14 miles off Brighton

The 142-metre long Margiris is owned by Dutch company Parlevliet van der Plas, which says it has an 'excellent reputation for sustainable fishing'.

A spokesman for the Blue Planet Society said: 'The capacity of these trawlers is equivalent to dozens of small-scale fishing vessels, and sustainable small-scale fisheries cannot compete with industrial supertrawlers.

'Supertrawlers are effectively floating factories and able to stay at sea for considerable periods of time. Margiris can process 250 tonnes of fish per day whilst at sea.

The giant ship can process as much as 250 tonnes of fish per day whilst at sea

'Local, smaller fishing boats have to return to port to offload the fish prior to processing.

'We think the supertrawlers Margiris and Annie Hillina are targeting mackerel off Sussex.

'This will undoubtedly put them in contact with short-beaked common dolphins, endangered bluefin tuna and overfished sea bass.'

The 142-metre long boat is owned by Dutch company Parlevliet van der Plas, which says it has an 'excellent reputation for sustainable fishing'. Pictured: A Greenpeace handout of the recent path of the supertrawler off the south coast

Clive Fennell, who lives in Littlehampton in West Sussex and runs the Littlehampton Environment and Places Facebook page, said he fears the supertrawler will have a 'devastating' effect on local fish supplies.

'Like with all environmental issues many people are very concerned, and worry about the future.'

Fishing in the Channel is governed by the Common Fisheries Policy (CFP), a set of rules laid down by the European Commission.

A Commission official said: 'The Commission is aware of concerns among NGOs concerning the activity of large trawlers (in UK waters).

'All vessels operating in EU waters, large and small, have to abide by the rules and this is controlled by the Member States' inspection and control services.

'It is a priority that all Union vessels comply with the legislation in force.

There are fears the ship's huge nets, shown here just off the coast of Brighton, will snag short-beaked common dolphins, endangered bluefin tuna and overfished sea bass in addition to their intended catch of mackerel

'Therefore, if there is a suspicion that vessels infringe rules then the Commission would like to be informed and receive concrete facts.

'Moreover, fisheries inspection authorities in the Member States also need to be informed about this.'

The Margiris was refused fishing licences in Australia in 2013, according to Greenpeace.

Clive Fennell, who lives in Littlehampton in West Sussex and runs the Littlehampton Environment and Places Facebook page, said he fears the supertrawler (pictured) will have a 'devastating' effect on local fish supplies

At the time, Greenpeace Australia spokesman David Ritter said: 'This monster is the biggest ship never to have fished in Australian waters.

'Like most Australians, we're happy to see the back of it.'

Greenpeace protesters confronted the Margiris - previously known as Abel Tasman - in West Africa in March 2012 and in the Netherlands and Australia in 2013.

A spokesman said at the time: 'We share the view of the small-scale fishers whose livelihoods would be destroyed by monster boats like the Abel Tasman: no monster boats here, not anywhere.'

Fishing company Parlevliet van der Plas includes the Margiris on a list of pelagic trawlers on its website.

The controversial Margiris (pictured), which has a deadweight of 6,200 tonnes, has been spotted off the coast of Sussex and Portsmouth over the last several days, according to MarineTraffic

The website says: 'Pelagic fish shoals are located with the help of echo-sounding equipment. From the echogram it is possible to estimate the depth and the size of the shoal.

'The net is towed behind the ship just below the water surface or further down the water column, but does not reach the sea bed.

'Pelagic fishing gear is constantly undergoing further improvements to ensure a responsible fishery through better selectivity.

'Special measures and aids - such as large mesh sizes in the front part of the net - are being developed to prevent the catch of un-wanted species or undersized juvenile fish.'

The company's website says it has an 'excellent reputation for sustainable fishing'.

'Our catch quotas are dictated by government and EU regulations, and are based on scientific advice.

'We fish without causing damage to the seabed, and without disturbing the ecological system.'