McCorkindale said HDC were keeping their finger firmly on the population pulse.
"We've had to, because previous population projections were not consistent with the growth we were seeing on the ground," he said.
"We were not anticipating hitting 35,000 people until 2022. We've got there three years earlier."
McCorkindale said there was a misconception that population growth in Horowhenua was due solely to a large number of retired people relocating from city centres, but latest figures showed that was not the case.
Although Horowhenua had an ageing population where 25 per cent were aged 65 or above - higher than the national average of 15 per cent - there was a marked increase in the number of people aged less than 65 moving to the area.
That trend was anticipated to continue in the next decade.
McCorkindale said growth forecasts required ongoing engagement with central government so it was aware of the way the district was rapidly changing and that it, too, could be proactive with infrastructure planning.
Horowhenua mayor Bernie Wanden said the groundwork council officers had already done in identifying the projected growth forecasts supported the need to be proactive rather than reactive to the growth forecasts.
"It's staggering. If you didn't have the numbers in front of you, you wouldn't believe it," he said.
"It highlights the work we have in front of us."
Long-term planning by council officers had already seen a master plan started for a new suburb to the east of Levin - Gladstone Green - earmarked for development that would enable a range of housing opportunities, shops, parks and a new school to help accommodate the growing Levin population.
Horowhenua District Council growth response manager Daniel Haigh said it was vital to pre-empt growth and put in place strategies to cope with the transformation.
"Horowhenua is in the early stages of district-wide transformation," he said.
"Our new strategy will help make sure development is managed well by taking into account future land needs, infrastructure, environmental protection, transport links, effects on existing residential areas, community development, and land for business and industry," he said.
Haigh said conversations with NZ Transport Agency would be paramount as council continues to lobby for much-needed roading infrastructure to protect the safety of road users and ensure connectivity.
Any population increase impacted on education, health services, infrastructure, traffic and social support services, and HDC was proactive in talks with government officials so they were aware of any funding priorities.
The population explosion was expected to have a significant impact on town planning and infrastructure with a huge rise in building consents and development.
He said the region's roads had recorded increased traffic volumes and the number of building consents had already risen dramatically.
Councillor Wayne Bishop said the building industry needed to be aware of what was happening, and work with education providers to maximise employment opportunities.
"We need to get the message out as soon and as broad as we can," he said.
Long term plans had previously forecast that 244 new dwellings would be needed each year to meet the growth in population.
That number had now doubled to an estimated 440 new houses, and there had to be enough builders and workers to cope.
Local builder Paul Tucker, who had built range of new houses in Australia and the upper North Island, said it made sense to come home and relocate his company TCON Builders to Horowhenua, as the region was on the cusp of a building boom.
Tucker said he would be looking to hire staff this year and was on the lookout for an apprentice builder.
Horowhenua had recorded the largest growth of any region in the Manawatū-Whanganui region, ahead Manawatū, Whanganui, Rangitikei, Palmerston North City and Ruapehu, and was in the top third of fastest-growing districts in New Zealand.
The parts of Horowhenua with the most population growth in the last five years were Ōhau-Manakau (360 additional people), Waitarere (267), Foxton Beach (264), Tararua (255) and Miranui (201).
Those same areas also had the largest increases in housing.
