The new wharf, which is estimated to cost between $170m and $190m, is expected to be completed by 2022.
Napier Port chief executive Todd Dawson said the port represented a long-term infrastructure asset.
He said at a news conference last month that log prices had fallen "after an extremely strong run" and he expected revenue from the log trade to level out this year before picking up again.
Napier, New Zealand's fourth biggest container port, said in a product disclosure statement, that 266,000 TEU (twenty foot equivalent) containers went through it in 2018.
In terms of bulk cargo - mostly logs - 3.07m tonnes were sent off in 2018. The figure is expected to rise to 3.38m in the current year, falling to 3.3m in 2020.
The port's earnings before interest, tax, depreciation and amortisation is forecast to increase by $2.5m to $39.7m in the current year.
But Napier Port's net profit is forecast to fall by $12m to $5.6m, reflecting $7.3m in share offer costs and an increase in finance costs due to the closure of interest rate swap agreements, worth $6.6m.
A rebound in net profit to $19.97m was forecast for 2020.
Under "market risks" the document said access to, or demand from, China and other key Asian markets may be "materially impaired".
Exports to Asian markets made up 84 per cent of the port's total exported cargo volume by weight in 2018 - 65 per cent to China.
About 90 per cent of log exports by weight from the Port were sent to China in 2018.
"If access to these key markets was impaired, or some other event occurred that resulted in the demand for cargo from the Port decreasing, this could have a material impact on our financial position and performance," the document says.
Industry sources said last month that logs are piling up on Chinese wharves as cheap, sawn timber makes its way by train into the People's Republic from Russia and Scandinavia, heavily undermining prices.