Treasurer Joe Hockey has cast doubt on whether the GST and company tax would exist in 30 years, as online trade and intense competition between countries erode these taxes as revenue sources.

"The world is changing remarkably, and whilst you would have easily assumed 10, 15 years ago that, for example, the GST is going to be an enduring tax ... with global trade, with the development of internet commerce, with not just the transaction of the sale of goods over the internet but increasingly services, there are going to be more and more goods and services that are provided from offshore under free-trade agreements that is going to miss that net," Mr Hockey told Sky News on Sunday.

"My view is you would have to question whether in 30 or 40 years' time taxes like the GST or company tax will be around," he said.