A cruise line that offered a 25 per cent refund to passengers on a construction-plagued sailing from Miami to Los Angeles has stepped up compensation in the wake of complaints.

Those vacationing on a Norwegian Cruise Line ship on a two-week voyage through the Panama Canal were disheartened to find that large areas of the vessel had been closed due to resurfacing work and other construction.

Passengers complained of thick dust and noxious chemicals and posted videos to social media showing crews loudly working away with power tools.

Victoria resident Wayne Jenkins said at one point, his wife nearly fainted after she was exposed to the chemical smell.

After complaints made to the company went public, NCL initially offered passengers a 25 per cent refund on a future cruise – valid only until March 31, 2019.

Many who shelled out big bucks for a trip they'd been planning for months balked at the compensation.

"If I want that 25 per cent, I want it in my pocket, because I don't want to give it back to NCL," Jenkins told CTV Vancouver Island.

The company has now revised its offer, promising a free cruise to affected passengers in a statement released Thursday.

"While we do our utmost to minimize any impact to our guests when these enhancements are being implemented, we do recognize that during a recent sailing, we did not meet the expectations of our guests, nor our own standards, for which we truly apologize," the statement read.

More than 2,000 guests who were on the Norwegian Sun voyage will receive a 100 per cent credit on a future cruise of their choice, valid until March 31, 2023.

"We realize that this gesture cannot replace their recent experience but do hope to have the opportunity to welcome them on board again soon," the company said.