Billionaire investor Alex Waislitz says "selfish behaviour" and "crazy indulgence" has put his home town in lockdown, but has warned Melbourne needs to open up to prevent a deepening of the long-term damage being done to the national economy.

Mr Waislitz is navigating what he says is the most challenging, difficult and unpredictable period in his 30-year investment career and has defended the performance of his listed investment vehicles Thorney Opportunities and Thorney Technologies, which are trading well below net tangible asset backing.