La Motte Street will be closed to traffic for seven weeks from next Monday (24 April).
The government is doing work there that it says will make town better for people who are walking and cycling.
Pedestrians will still be able to get to the Customer and Local Services and Revenue Jersey offices at Philip Le Feuvre House.
Many people are likely to be heading there over the coming weeks to hand in their Income Tax Return before the paper deadline of 31 May, although the authorities have been encouraging islanders to switch to online filing.
An artist's impression of the junction at Hilary Street
The first phase of work will be between the Hilary Street and St Saviour's Road junctions and involve improvements to surface water drainage, street lights, replacing concrete slabs with new paving and resurfacing the road.
During the road closure, vehicles will be able to drive in and out of Berkshire Court garage, and to the disabled parking bays on Hilary Street.
Diversions will be signposted and the bus stop on La Motte Street will be suspended. Grenville Street is the next nearest stop.
The second phase of the work will involve what the government calls 'major public realm improvements between the Hill Street and Hilary Street junctions. Those changes are 'currently being designed'.
A full schedule of the planned work is on the government website, though dates could change depending on the weather.
Infrastructure Minister Deputy Tom Binet says cars stopping along La Motte Street has caused problems:
“La Motte Street has suffered from unstructured parking and drop off, causing problems for buses using the street, and risks to pedestrians trying to cross the road between vehicles stopped in undesignated areas."
The completed work will provide an onward link from the Hill Street contraflow cycle route.