Companies were expecting an average £78 million a year in work but draft budgets show a private sector spend of just £25 million in 2006-07 and £40 million in 2007-08. This year's budget is £39 million.
'The Treasury isn't giving the Roads Service the money to do the job. Over the next two years we're looking at a return to pre-1995 spending levels.'
Mr Best met Roads Service chief executive Ian McKibbin yesterday (Wednesday) to underline industry concern.
He wrote: 'Over the past two years many companies have invested heavily - up to £7 million - in upgrading their existing production plants and indeed acquiring new plant.
'All this was done on the basis that there was going to be significant investment in the structural maintenance programme.'
He will also hold talks with regional development minister Shaun Woodward in December.
The QPA is also concerned that lack of investment in the Northern Ireland road network - which stretches 25,000 km with an estimated asset value of £20 billion - will discourage overseas investment.
The Roads Service made an extra bid for £15 million in June but was rebuffed by the Treasury.
Mr Best added: 'Companies intending to invest in Northern Ireland will look at the Republic of Ireland as a more favourable place to invest due to its higher infrastructure spend and more efficient road network.
'We will be returning to the days of the dirt tracks in comparison to other European countries.'