Using "non-traditional" ways to fund major projects like the NBN and student loans is threatening the federal budget position and leading to calls for an overhaul of how the nation's finances are presented to the public.

The independent Parliamentary Budget Office, in a report into so-called "alternative financing arrangements", found it is becoming increasingly difficult to scrutinise the nation's finances as more projects are funded off-budget.

The NBN is funded via an "alternative financing arrangement". The Parliamentary Budget Office says these arrangements, if not properly recognised, could hide long term budget issues. Credit:Peter Braig

The Morrison government is expected to use loans, guarantees and equity injections as part of its package of measures aimed at protecting the economy through the financial fallout from the coronavirus pandemic.

These type of measures do not appear directly in the budget including the underlying cash balance, which in the mid-year update was forecast to show a surplus of $5 billion. The government has already conceded this year will show a large deficit.