A significant increase in the number of "plane people" seeking asylum in Australia has resulted in the country's longest refugee wait list in history, according to new figures from the United Nations' peak refugee agency.

Over 60,000 people had refugee applications before Australian government officials by the end of 2018 in what is a dramatic uptick from the nearly 30,000-long 2016 waitlist.

Kristina Keneally said the people arriving by plane to Australia before claiming asylum was a sign the people smuggler trade was evolving under Peter Dutton's watch. Credit:Alex Ellinghausen

The new figures from the United Nations High Commission on Refugees add fire to a growing clash between Home Affairs Minister Peter Dutton and Kristina Keneally over the marked increase in so-called "plane people" arriving in Australia.

The last few years have seen a surge in people arriving in Australia by plane on legitimate tourist visas before later claiming asylum - 81,000 have done so in the past four years.