Some think that erosion problems, which have resulted in the loss of numerous beachfront homes, have increased because of the weakened condition of the south and north jetties.
MRBA leaders say that fortifying both jetties could act to limit erosion, which now is affecting Salisbury Beach and the south end of the inhabited part of Plum Island.
When fully functional, the jetties have been effective in warding off strong winds and waves, local officials say.
The south jetty is 2,445 feet long, and the north jetty stretches 4,118 feet, according to state officials.
Construction managers say the work on the south jetty should be finished by March 31, a date that coincides with the arrival of federally protected piping plovers.
Local officials did not have a date when work on the north jetty will start, in part because requests for proposals (RFP) have not yet been extended, said Dan Rubin, a spokesman for Tierney.