"The plan is to have one lane operational right around the roundabout by the end of the week - weather permitting.
"As soon as one roundabout lane is fully functioning Napier Rd can be reopened."
Work on the roundabout is expected to be complete by the end of this month.
It is one of three roundabouts planned for the 3.5km road, which will not be fully finished until late next year.
Work has begun on a bridge to be built over Karamu Stream, which is expected to continue for a further two weeks.
Installation of bridge beams is expected to begin in four to six weeks' time.
Napier Port chief executive Garth Cowie said the Whakatu link would be very good for businesses transporting goods outside the region.
"[It] will improve the efficiency of the overall local supply chain by providing a quicker and more direct route to the port."
The Hawke's Bay Regional Council planned to create a new park as part of the Whakatu link development.
Jenny Chetwynd of the Transport Agency (NZTA) said when the project was announced that it was designed to help economic growth.
"Freeing up access to the Port will make the Hawke's Bay economy more competitive, and unlock further potential for economic growth."
The Government contributed just under $18 million to the project through NZTA - the remainder of the $26m required would come from ratepayers.
It is the largest roading project undertaken in the region since the Napier-Hastings expressway in 2002.