According to the bill's backers, such a mandate could help spark a $10-billion supply chain industry.
The contents of the bill, which has yet to be introduced, remain in flux.
Danish developer Dong Energy and Offshore MW — affiliated with Germany's WindMW – are planning major offshore projects off Massachusetts. US developer Deepwater Wind is also trying to start two major projects off the north-east US coast.
"The Massachusetts legislation would ignite the US offshore market," said a spokesman for offshore wind turbine manufacturer MHI Vestas.
"We currently have no plans to open a factory in the US, but if the bill passes and the market can sustain 1GW year on year, then we would definitely consider a local US supply chain footprint," he said.
"History has shown that ... the early movers are traditionally the ones that reap the supply chain benefits," the spokesman added.
Massachusetts' current legislative session ends on 31 July, and proponents hope to introduce the bill by then.