The main route through the island's capital reopened on Wednesday after six and a half weeks of work to change the road layout.
Colin Le Page said: "It shouldn't have a huge impact... studies show it won't be huge delays.
"But there's a huge improvement for pedestrian safety."
The increased pavements size, signage and barriers follow a move to disembark cruise ship passengers from the Albert Pier, rather than the inter-island quay.
Some parking spaces at Albert Pier and the bus terminus will be unavailable on days when cruise ship passengers are visiting the island.
The aim is to ensure pedestrian safety and make space for coaches to pick up passengers for tours.
Mr Le Page said the "temporary" changes would be monitored for a year before a long-term decision was made.
The States estimate the total economic value of the cruise liner industry to the island is Â£6m a year and expects it to rise with more passengers due to come ashore this season.
"Small delays" will be caused by the merging of two lanes of traffic in St Peter Port, admits Guernsey's principle traffic officer.