Despite the new Nowra bridge being built over water, construction will have a "major" effect on traffic, said Kiama MP Gareth Ward.
"I have to be blunt - there will be major traffic implications but there's just no alternative," Mr Ward said.
"We have a bridge that has reached the end of its serviceable life. We need to build a bridge that's going to last another 100 years. Will there be short-term impacts? Yes. Will there be long-term benefits? Absolutely."
READ MORE: Builder of new Nowra bridge announced
Mr Ward said Transport for NSW initially planned to close Illaroo Road for 12 months, but he said he wasn't going to stand for that.
"I think the major impacts will be experienced by people in North Nowra and Bomaderry," he said.
"There will be impacts from motorists coming from the north and the south, but as we work on the turning lane out of Illaroo Road."