The Massachusetts economy is expected to grow slowly before accelerating in early 2014, benefiting from a boost from an unexpected sector — manufacturing — according to an economic forecast released Wednesday by a group of regional economists.

Although Massachusetts is in the midst of a slowdown in hiring, the five-year forecast by the New England Economic Partnership shows the state’s economy adding jobs at a significant pace beginning next year. Employers will add about 30,000 jobs this year, about 50,000 next year, and more than 70,000 in 2015, according to the forecast.

The state’s unemployment rate, 6.4 percent in April, is expected to average 6 percent in 2015 and fall to about 5.2 percent by the end of 2017, the report said.

“The outlook for the future is much better than it has been and that has a lot to do with restoring confidence and consumer demand,” said Alan Clayton-Matthews, a Northeastern University economics professor and director of the New England Economic Partnership, a nonprofit forecasting group of academic and business economists. “By 2015, we’ll be in a growth spurt phase of the recovery where people’s spending catches up to their wants. The jobs, they’ll be there and people will be willing to spend, which begets more jobs.”

The New England Economic Partnership issues forecasts twice a year for the region and each of the six New England states. The forecasts sometimes have proven more pessimistic than the eventual performance of the economy, and sometimes more optimistic.