The NEA said it now expects just 2GW to be operating in Chinese waters by the end of next year due to higher costs than previously expected. It also slashed plans for 2020, knocking 20GW off its target, and revealing an intention to install just 10GW by the end of the decade.
The NEA warned in March that it would not meet its 2015 target, but did not specify at the time how much it would miss by.
This shortfall has been predicted despite the NEA introducing a long-awaited pricing scheme for offshore wind power in June.
It set the offshore feed-in tariff at CNY 850/MWh ($130), which has been challenged by some commentators as too low to spur the kind of scale of development that China is aiming for. The price is about half of the $262/MWh that the UK's pays for offshore wind energy.
China currently has 428MW of wind capacity operating offshore.