A pair of US telecom carriers on Wednesday postponed selling Samsung's latest flagship smartphone, citing delays in shipments from the South Korean consumer electronics giant.

T-Mobile had intended to start selling Samsung Galaxy 4 smartphones on Wednesday, and rival Sprint had planned to add the smartphones to its line-up at real-world stores as well as its online shop on April 27.

Sprint will take online orders as planned, but will have Galaxy 4 smartphones in its physical stores as inventory becomes available.

"Unfortunately, due to unexpected inventory challenges from Samsung, we will be slightly delayed with our full product launch," Sprint said in a release.

T-Mobile set Monday as the new target date to begin selling the Galaxy 4 online and said it would begin getting the smartphones in its stores the second week of May.

"Due to overwhelming global demand of Galaxy S4, the initial supply may be limited," Samsung said in a released statement.

"We expect to fulfill inventory to meet demands in the coming weeks."

Unveiled last month at New York's Radio City Music Hall, the touchscreen device goes on sale in South Korea on Friday and will roll out globally over the weekend.

The Galaxy S4, armed with eye motion control technology that will pause a video when the user looks away, comes with a faster chip and is thinner and lighter than the previous S3 model.

After years of following and refining the iPhone's pioneering innovations -- a strategy that resulted in bitter patent battles with Apple -- Samsung has dethroned its California-based rival to become the world's top smartphone maker.

With that title has come increasing pressure for Samsung to shed its copycat label and come up with its own game-changing innovations.

"Samsung has entered territory that it hasn't been in before, and sales of the S4 will show if can sustain its newfound status in the market," James Song, analyst at KDB Daewoo Securities, told AFP.