THE value of major investments in Australia fell nearly $25 billion in the December quarter, a leading economic forecaster has estimated.

While the broader economic outlook is looking more positive, the Deloitte business investment monitor also found a $7.4 billion fall in potential projects over the quarter.

The monitor found projects already committed or under construction fell almost $25 billion in the December quarter, the biggest fall since December 2008.

That drove the value of definite projects down by 1.2% in the past year, while the total value of potential projects (not yet committed), fell 9.2% over the past year.

But it was not all bad news, with forecasters welcoming a lower Australian dollar, with associated relief for exports, and strong growth in house prices and retail sales.

However, the end of Holden manufacturing in Australia, a raft of off shoring decisions and a rising unemployment rate created a mixed outlook for this year.

Key to riding out expected weaker growth could be infrastructure investment, with potential for such investments to drive some resurgence, if it eventuates.