The CPA is worried that any reduction in central government income may lead to funds being diverted from essential public building and road repairs to more politically sensitive areas, such as teaching salaries and the NHS.
Allan Wilén, the CPA's economics director, said: "Our latest forecasts suggest that the [maintenance] area would be under pressure if resources were reallocated away to areas such as teachers' pay. For many sectors in maintenance, it's a pretty flat picture."
Wilén added that Brown had to monitor increases in other areas that might take money from government coffers.
He said: "There has been a general upward trend in public sector pay over the last few years. One of the government's challenges will be checking that."
The CPA is also concerned that local authorities, faced with a shrinking pot to fund all their services, will focus on paying politically vital bills, again such as teachers' pay, and cut back on less sensitive areas such as building maintenance.
The government has increased its revenue spending over the past few years at a faster rate than its investment spending. In the same period, there has not been the same rise in taxation.
Major public works infrastructure is funded out of investment spending but lower key maintenance jobs are paid for out of current revenue funding. Many of these depend on the public sector for money.