Japan intends to send its whaling fleet back to the Antarctic this year, a senior official has told BBC News.
Another is financial. Japan's national budget was in trouble even before the impact of the recent earthquake and tsunami; and with sales of whalemeat falling, the cost of the hunt is rising.
But Mr Morishita suggested all of these issues would be easier to overcome than Sea Shepherd's opposition.
Some observers have suggested that Japan sees blaming Sea Shepherd as a way to escape from Southern Ocean whaling without losing face.
Mr Morishita said this was not the case, and the basic policy remained unchanged.
Sea Shepherd activists have staged demonstrations outside the IWC meeting here – the organisation is barred from attending – and it is clear that it will send its fleet to the Southern Ocean again if Japan does return.
"Sea Shepherd will also return and will once again intercept and block their operations," the organisation's head Paul Watson wrote on his blog earlier this week.
"If they return, we will launch Operation Divine Wind, and our vessels the Bob Barker, the Steve Irwin, and the Brigitte Bardot will soon return to the remote and stormy seas of the Southern Ocean Whale Sanctuary to do what we do best – defend the whales!"