Further investment into the Airport and Sea Terminal would likely be needed if the Island reached the target of 500,000 visitors by 2032.
That's according to Infrastructure Minister Chris Thomas, who was asked what the impact that number of visitors would have on airport and harbour usage.
Mr Thomas noted that some existing air and sea routes are not currently operating to capacity, and so the extra people may just fill seats already available.
Airlines may then look at using larger aircraft to accommodate extra demand.
It's added that the department is currently undertaking a refurbishment programme for the Sea Terminal Building, which is funded for the first two years.
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