DUTCH marine transportation company Nedlloyd and US shipping company Sea-Land Inc are not discussing a merger, says Nedlloyd spokesman Peter Knottenbeld. Dutch newspapers have reported during the past few days that a merger is being considered by the two companies. Mr Knottenbeld said, however, ''there are no such discussions taking place''. The two companies are discussing ''operational matters'', he said. ''When we talk about operational matters we talk about matters affecting out trade,'' Mr Knottenbeld said.