Officers will police the crossing when ships with more than 1,500 passengers visit – of which 40 are scheduled to arrive between now and early October.
The Environment Department said the move had nothing to do with the new traffic arrangements at The Quay but the fact that the cruise liner passengers could increase the volume of people using the crossing to more than the upper limit for a courtesy crossing of 600 people per hour.
A spokesman for the Public Services Department, which has responsibility for the harbour, said the cost of manning the crossing would be about £800 per day.
The department has been criticised by some for its decision to berth cruise liner tenders at the Albert Pier instead of the Inter- Island quay.
The PSD spokesman said an allowance of around £10,500 was included in the relocation expenditure.
'If the arrangements for manned crossings are required on all the busiest days this season, that cost is likely to be around £30,000,' he said.
'That would represent what we think is a worst-case scenario, because as with the other arrangements the manning requirements could be kept under review during this initial season.'
