"They have every reason to be upset," he said Monday in an interview of coastal enclaves such as Hopedale and Makkovik that haven't had major freight deliveries by ship since the fall.
McGrath said he hopes to have mechanical and lifeboat issues sorted out and supplies en route as early as this weekend.
In the meantime, he said he's looking into offering extra help from the Newfoundland and Labrador government to fly in supplies.
Community leaders say store food stocks are low or out of many staples along with other items, such as diapers and dish detergent.
"I'm as upset as they are because when you put out a contract you hope to have it work efficiently and effectively," McGrath said of service agreements with Nunatsiavut Marine and Labrador Marine Inc.
Neither company could be reached for comment.
Hopedale Mayor Wayne Piercy said the community of 650 is down to very few store items.
He said the last major ferry delivery was in late November and supplies have been running low since Easter.
Piercy said some fresh produce is flown in once a week but he's worried that children especially aren't getting the nutrition they should.
"We've been very vocal about how low our groceries are here in town," he said. Many families have relied on a community freezer stocked with moose meat, seal and cod, he added.
"It's getting to a point now that for the majority of children here we don't know what they're actually eating because nobody here has got anything in the stores."
Piercy described Monday what's left to eat in the Big Land Grocery, one of just two places to buy food in the community, as a small assortment of canned soup, canned meat and some Chef Boyardee pasta.
McGrath said he's looking into how "management procedures" might have helped ease some of the most recent issues. A cargo ship, the MV Astron, recently couldn't dock at Lewisporte to load up with groceries destined for the Labrador coast because the MV Sir Robert Bond passenger and freight vessel was already parked in one of two berths.
A specialized crew to move the Bond couldn't respond "at a moment's notice," McGrath said.
The other berth was taken up by the MV Northern Ranger. Lifeboat issues have delayed its usual runs up the Labrador coast.
"This is a contracted service," McGrath said. "And when we contract the service we expect the best service."
Piercy described the situation with the MV Sir Robert Bond as particularly "ridiculous."
"How did the boat get to where it got if there's no crew to run it?"
Legislature member Randy Edmunds, who lives in Makkovik and is the Liberal party's critic for Labrador affairs, said the government had all winter to ensure its vessels were ready to deliver crucial spring cargo.
He described low and sometimes non-existent supplies of flour, tissue and sugar.
"The shelves are pretty much bare. They're flying in enough so people won't starve to death but the bulk of the freight from the wholesalers is still sitting in Lewisporte."
Marine contractors provide a service but the province must supply adequate vessels, Edmunds said in an interview.
"And that's where the problem lies: having the vessels ready and operable. Either they don't know what they're doing or they don't realize how serious the situation is.
"If this were anywhere else in the province, heads would roll."
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