The NI Executive needs to raise additional revenue by introducing water charges, a group representing property professionals has said.
The Royal Institution of Chartered Surveyors said capital spending on construction projects was one of the best ways to stimulate the economy.
It said funds should also be raised for capital spending by switching money from day-to-day budgets.
It added that there was a question mark over plans to sell off assets.
The draft budget is intended to save a cumulative £4bn from NI expenditure by the end of 2014-15.
It has been heavily criticised in some quarters with a report by management consultants describing it as a "patch and mend approach".
The draft budget includes plans to raise hundreds of millions of pounds by selling property owned by the government.
Lack of clarity
"We have concerns about the ability to raise such sums in the current market, particularly when Nama will be active during the years ahead," said Ben Collins, RICS NI Director.
"Not being able to raise this revenue would clearly have significant implications for capital spending."
He added that there was a lack of clarity on plans for housing associations to contribute £20m a year to support investment in social housing.
He said he understood that the executive was short of money for its capital budgets but added that water charging "was strongly in the interests of the economy".
The RICS recently published its own manifesto, including calls for reform of the planning system to fast-track projects of significant economic importance.
It also made an appeal for reform of public sector procurement to enhance transparency.