The air force's Ohakea base has been unstaffed overnight since the pandemic, effectively closing New Zealand to overseas aircraft in some circumstances

Currently, long haul flights must carry an extra six tonnes of fuel in case a last minute landing change from its original destination, is required.

The base, just outside of Palmerston North, acts as a back-up runway if Auckland or Christchurch are unavailable.

Board of Airline Representatives Executive Director Cath O'Brien says a lack of rescue crew and firefighters limits the number of planes that could come into the country.

She says aircraft can only fly between early morning, and late evening, something that could change with 24/7 staffing.