(Reuters) -More than 45,000 U.S. dockworkers represented by the International Longshoremen's Association ratified a new six-year contract on Tuesday, formalizing a deal that offers bumper pay hikes and averts any potential disruption until 2030.

Terms of the contract, previously agreed upon by the labor union and the United States Maritime Alliance, included a 62% wage hike over the life of the agreement.

Both the labor union and the employer group had agreed on the wages in October, putting an end to a three-day strike that spiked shipping prices and caused cargo backlogs at the three dozen affected ports.

But they remained divided over issues tied to automation. It was not until January that a tentative deal was signed, which was also a priority for the White House.

The new contract, which will be in effect from Oct. 1, 2024 to Sept. 30, 2030, increases the hourly base rate for workers to $63 from $39, ranking longshoremen among the highest paid blue-collar workers in the U.S.

It accelerates wage raises for new ILA workers, strengthens healthcare plans and also increases employer contributions to retirement plans, while safeguarding workers from threats of increased automation.

The workers approved the new contract by a resounding 99% vote. ILA and USMX said they will sign the agreement on March 11.

"We now have labor peace for the next six years," ILA President Harold Daggett said. He previously claimed the new contract will cost employers an estimated $35 billion.

"Our collective strength helped produce the richest contract in our history," he said in a video to the members of the union last week.

The agreement offers some relief to shippers, who operate in an uncertain environment due to factors such as disruptions in the Red Sea and the looming threat of new tariffs.

Both the ILA and USMX have previously credited President Donald Trump for clearing the way for them to make a deal on automation.

The 36 affected ports were some of the busiest in the U.S., including the port of New York and New Jersey, and together account for more than half of the country's imports.

The employer group, represented by USMX, counts Maersk's APM Terminals and the U.S. arms of major container carriers such as China's COSCO Shipping as some of its members.

(Reporting by Abhinav Parmar and Nilutpal Timsina in Bengaluru; Editing by Tasim Zahid and Arun Koyyur)