Air New Zealand chief executive Greg Foran last week said the airline would require all domestic passengers to be fully Covid-19 vaccinated or produce a negative test result from the middle of next month.
And KiwiRail says senior staff are considering various options for vaccine mandates for travellers on the Interislander ferries between Wellington and Picton.
A KiwiRail spokesman said there was no firm timeline for a decision. In the meantime, the ferry operator was enforcing the Government requirement to wear masks while travelling.
"KiwiRail has followed all Government advice and requirements in responding to Covid-19, and will continue to do so," the spokesman said.
Air Chathams, a key regional carrier, is likely to do the same as Air New Zealand to manage domestic travel safely.
The Government is expected to set out this week when and how Auckland's boundaries will re-open, and one option is closing off lower-vaccinated areas or opening them only to the vaccinated.
Prime Minister Jacinda Ardern has said allowing Aucklanders to leave for summer was a "bottom line" for the Government.
Foran said a survey of customers found an overwhelmingly majority said "please get on and do this".
The tough move follows the airline's decision to require vaccinations for international flights and growing concern during the Delta outbreak about unvaccinated passengers flying from Auckland to other parts of the country.
Air New Zealand aims to have the change in place by December 14 for an initial period until the end of March 2022.
It will apply to all passengers aged 12 or older travelling on an Air New Zealand aircraft within the country. All vaccines and tests approved by the Government will be accepted.
Air Chathams chief operating officer Duane Emeny said other domestic carriers were likely to follow Air New Zealand.
