Highways England is carrying out overnight maintenance on Bascule Bridge, which connects the south of Lowestoft with the north.
The bridge will be closed between 8pm and 6am from Monday August 2-Friday August 6.
Bascule Bridge will remain open over the weekend.
A diversion route will be in operation and with the closure in place "delays are likely" according to the Suffolk Roadworks map.
It said: "A47 northbound and southbound Bascule Bridge, Lowestoft - carriageway closure and diversion route due to maintenance works on behalf of Ringway."
Travellers using First Eastern Counties Buses are being warned of the temporary closure.
Last week, a post on the First bus website said: "The Bascule bridge in Lowestoft will be closed overnight from 8pm until 6am.
"Buses will be on diversion via Oulton Broad. We are sorry for any inconvenience this may cause."
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