Cook Strait ferry company Interislander has reduced the number of passengers on each sailing for people travelling home this week.
Ships usually carrying 1300 passengers are now taking 500, and ships with a capacity of 500 have been halved to help with social distancing.
The company's CEO, Greg Miller, says crew members have also marked out sections of two metres in the terminals and on the ships to help passengers observe the rules.
Miller says 9000 people will be travelling home across Cook Strait this week, most heading from the South Island to the North.
The travel deadline for the Covid-19 lockdown is Friday at midnight.
Earlier in the week, KiwiRail decided to provide an extra two days' sailings of its Interislander ferries - moving an extra 3000 people in each direction.
Passengers were being treated as a priority over freight on sailings of the Kaiarahi and the Kaitaki, he said.