Traffic backs up on Rangitikei St at the intersection with Tremaine Ave in Palmerston North.

Drawn-out roadworks at one of Palmerston North's busiest intersections have been labelled a "six-month nightmare" amid a slew of complaints.

The Tremaine Ave intersection with Rangitikei St is being upgraded as part of a $2.8 million makeover, which began in August last year.

Major works are expected to be completed by the end of next week. Minor work may be done after that but it will not affect the road.

The project was intended to ease peak-hour delays. In August the NZ Transport Agency said the project would reduce average waiting times and help the intersection run more smoothly.

However in doing so, the works have ended up exacerbating the problem it set out to solve.

Horizons Regional Council chairman Bruce Gordon regularly travels through the intersection and described it as a "six-month nightmare".

On Tuesday, he said that it took him 25 minutes to get from the over ramp to Victoria Ave, where the Horizons offices are.

He said the traffic did not seem too bad during the school holidays, "then school went back – it seems diabolical now".

The congestion entering the city was so badly backed up it often extended as far as Flygers Line. Gordon suggested fulltime closures to get work done quicker.

Palmerston North mayor Grant Smith said Gordon was not alone in his frustration.

"His story is one of many."

He said there were alternative routes such as through Milson and Cloverlea that could have been used if a full closure had been done.

"If you go overseas it just happens – Auckland and Wellington would not put up with this.

"It's not just the frustration, it's the loss of productivity, it'd be huge."

Gordon said he recently spoke to NZ Transport Agency central regional director Raewyn Bleakley about the issue of shorter, but complete closures, instead of longer works with access.

He raised the idea of giving people an option to consider a "three-week closure or a six-month nightmare".

"I think most people would opt for the shorter time frame."

Smith agreed with Gordon on the idea of full closures.

"It is a major intersection, we need to ask the question 'do we close it and work night and day to get it open again?' Rather than six months of consistent semi-closure."

Bleakley told Stuff that wherever possible the work had been done outside of peak traffic times to minimise disruptions.

"Carrying out the work during less-busy off-peak times – and avoiding disruptive work during peak times – has extended the overall construction period for the project."

Bleakley said a full road closure at Tremaine Ave may not have been possible, but they would look at the possibility of doing it in other areas in future.

"We will be consulting the public and considering all of the options available for any future work carried out, such as partial closures of the state highway, night work and working outside peak travel times.

"While full road closures can accelerate the completion of road works in some cases, it would be very difficult and disruptive for drivers to close this particular intersection, as both Rangitikei St and Tremaine Ave provide key connections to the wider local transport network.

"It is one of the busiest intersections in Palmerston North, with Rangitikei St being the key road to Whanganui. Additionally, Tremaine Ave is a key east-west link for freight, leading south to Wellington."

Bleakley said some delays had been caused by the need to upgrade underground services.

"We understand that these delays are frustrating for people and we apologise for the inconvenience caused."