After two years of discussions, Australian and New Zealand Customs are planning trials to clear passengers before they board flights between the countries.

An Open Skies bilateral air services agreement is already in place, easing the rules for carriers flying between the two countries. But quarantine, security and immigration issues have to be addressed to make the route a common border.

The trials will look at creating a clearance system similar to those used for passengers travelling from Canada into the United States and in Europe across European Union countries. Once they are cleared at their point of origin passengers enter any port as a domestic visitor.

Air New Zealand, Qantas, Jetstar and Pacific Blue believe the move could result in fares being cut by up to 30 per cent. Jetstar's chief executive, Bruce Buchanan, discussed the trials with politicians and officials while in Auckland last week.

He announced plans to launch Jetstar's domestic presence in New Zealand from June. "There is a political will for a common border," he said.

New Zealand's Customs Minister Maurice Williamson endorsed the move: "The Government supports the consideration of initiatives that potentially improved trans-Tasman travel."

A government and industry working group has proposed two concepts for consideration: trials of fully and partially cleared flights between Australia and New Zealand. Partially cleared flights would probably involve only New Zealanders and Australians. Fully cleared flights would cover all passengers, no matter what nationality.

Three Australian automated border processing "smartgate" kiosks were installed at Auckland International Airport last September to speed up entry into Australia.