He said there were 280 people working on the site before Christmas but that has reduced significantly to less than 100 people on site.
The project, which is 20% complete, installed the largest ever beams delivered to a construction site in the UK or Ireland before Christmas, which measured 49.5 metres.
Mr Barrett said there are more beams being delivered from Portugal, steel beams for the Bohill structure on the western side of the site near the county bounds.
County Hall’s Director of Roads also said that the assistance of An Garda Síochána would be needed in certain circumstances such as the delivery of the steel beams to the site and blasting activities on site which are continuing.
Mr Barrett also warned there were two road closures coming up in the months ahead, at Kilnagurteen and Clonfadda.
The 22km Macroom bypass, which is costed at €280m, is on schedule to open by 2023.