"Our decision will be based on our technical assessment of the road, which considers factors like crash history, road environment and speeds that people generally travel at, as well as feedback received during consultation from the general public and stakeholders."
Stewart said part of the legal process meant a new by-law must be published 28 days prior to a speed limit "becoming legal".
"Any changes will not occur during the holiday period."
Motorists raised concerns about extended journey times after the plans were announced earlier this year by the NZTA, which were part of a series of road safety changes for Hawke's Bay including for SH51.
'Gloves off' for speed enforcement along SH51
Police have warned motorists they will begin issuing tickets for people breaching the new speed limit along SH51 between Clive and Napier.
The speed limit dropped from 100km/h to 80km/h along that stretch of road at the end of October to improve road safety.
It was part of the NZTA's review of both SH5 and SH51.
"While there have been some instances of people driving above the new speed limit, it's not unexpected in these early days. Generally, we are pleased with how quickly motorists have got used to the changes," Stewart said.
During the first month of the speed limit changes on SH51, police have largely taken an education-first approach with motorists.
However, Eastern District Police road policing manager Inspector Matt Broderick said that would change from this week.
"Generally speaking, we leave [motorists] about a month and that has just finished, so the gloves will be off," he said.
"Whereas before we might have given them advice, they can expect to start getting tickets from now on."