The uneven surface of State Highway 1 at the railway crossing north of Maheno is expected to be temporarily fixed within 10 days.
Since late last year, signs on both sides of the crossing have been in place warning motorists to reduce their speed to 50kmh due to the uneven surface.
New Zealand Transport Agency journey manager Graeme Hall said the issue was with underlying foundations of the railway line.
NZTA had been investigating the problem with KiwiRail.
Mr Hall said a long-term solution was needed, but the surface required immediate attention.
Within 10 days, Mr Hall said the surface would be smoothed with tarseal as a temporary measure.
''It is very rough ... that surface isn't satisfactory,'' he said.
NZTA hopes to have a long-term solution to the foundation issues within the next 12 months.
