Air New Zealand's new Buy on Board service is proving a hit with domestic customers, with the airline regularly exhausting its supplies by the end of the day.

The airline launched its new service on its 737 domestic fleet on March 12, to provide customers with a variety of healthy, nutritious food and beverage choices.

A range of Wishbone products are available for purchase on board, including fresh fruit salads, sandwiches, salads and sweet treats.

On April 5, Air New Zealand General Manager Domestic Airline Bruce Parton said that customer demand in the first two weeks had exceeded the airline's expectations.

"Customers are telling our crew how pleased they are to have the choice of purchasing food that's healthy and substantial during and at the end of a busy working day," he said.

Customers had indicated they were comfortable with the product that were being offered and the pricing, which ranges from NZ$3 - NZ$7.

Mr Parton said the airline was regularly selling out of the two varieties of Wishbone sandwiches, which had proven the most popular product choice. As the result, the airline had increased the quantities on its flights to ensure customers later in the day were catered to.

Fresh fruit salad and a berry yoghurt trio were also proving popular, with a number of customers purchasing these to take home.

"Cabin crew have also reported a jump in the number of beverages being purchased, as customers enjoy a wine, beer or soft-drink with their meal."

Mr Parton said the airline would continue to tweak its product selection in response to customer feedback. As a result of requests from customers it is also considering rolling out the service on the A320 aircraft that occasionally operates on domestic 737 routes.

"We also see great potential to offer a range of premium beverages on domestic flights - this is something we'd be interested in exploring," Mr Parton said.