The new system will see the two-lane access maintained from Cameron Rd to Tauranga District Court, then McLean St will become one-way through the Willow St intersection and down to The Strand.
"We were very conscious when working on the design that we didn't disrupt the operational activities of the courthouse," he said. "That was a crucial point."
Mr Parkes said safety was the main reason for the change. Studies had found the intersection of McLean and Willow to be concerning.
"We've had a problem with crashes at that intersection for a while. Also there's a lot of pedestrians who walk up and down in the area, particularly in Willow St. Crossing McLean Street is not ideal."
The changes would narrow the road and extend the kerbs so that crossings would be less intimidating, he said.
Mr Parkes noted that the council had already created a one-way system at nearby Park St and would assess other streets parallel to McLean St.
"There are other works in the pipeline, but we just haven't got to the stage of implementing them yet. We'll be picking off a lot of these bad intersections as time goes on as other works are planned in the system."
He noted that part of the city centre project involved upgrading Durham St.
"A lot of the intersections along Durham St have got worse crash records than Willow and McLean," he said.
"You just pick off the ones you can do at any one time. It's part of a process where we want to make sure the hub environment is a little bit more friendly for pedestrians as they walk down."
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Mr Parkes said council had consulted McLean St businesses about the changes. As a result, the scheme had been tweaked to ensure one retailer had adequate truck access.
Mary McDonald, the manager of the Aspen Rest Home, which is almost opposite the courthouse, said she did not believe the changes would make any difference to the home's access. However, she said it could make the area more user-friendly for pedestrians.
Doug Lyon, the director of law firm Lyon O'Neale Arnold, which is on the corner of Willow St and McLean Rd, said there had been a significant number of crashes at the intersection. The most dangerous ones occurred at right angles.
The firm did not have any issues about the proposed changes.
McLean St changes - Will create 23 new car parks - Will make the street one way - Will occur by the end of April