WASHINGTON (Reuters) - The union representing 45,000 East Coast and Gulf Coast dockworkers and a group representing employers held a new round of contract talks this week but failed to make significant progress on some key issues, the employers group said on Wednesday.

The International Longshoremen's Association union agreed to end a three-day strike on Oct. 3 after it won agreement for a 62% wage hike over six years with the United States Maritime Alliance (USMX) employer group following significant involvement by the White House and other Biden administration officials.

The work stoppage was the first large-scale strike at East and Gulf Coast ports in nearly 50 years, briefly halting the flow of about half the country's ocean shipping.

USMX and the union met for two days this week in an effort to reach a new six-year contract ahead of a Jan. 15 deadline.

"While we had positive progress on a number of issues, we were unable to make significant progress on our discussions that focused on a range of technology issues," USMX said.

"Unfortunately, the ILA is insisting on an agreement that would move our industry backward by restricting future use of technology that has existed in some of our ports for nearly two decades, making it impossible to evolve to meet the nation's future supply chain demands," the employers group said.

The key outstanding issue remains the use of automation at the ports. The Biden administration is concerned about the prospect of a new work stoppage next year, a senior official said.

The ILA declined to comment.

The union earlier demanded the employer group stop port automation projects that it says threaten jobs. USMX said on Wednesday it is "not seeking technology that would eliminate jobs."

The tentative deal announced last month would raise average wages to about $63 an hour from $39 an hour over the life of the contract. That is contingent on the rest of the issues being resolved.