Samsung said it cannot confirm the shipping date for its foldable device Galaxy Fold yet and apologised to its pre-order customers in the United States for the delay.

The world's top smartphone maker delayed global sales of the splashy $US1,980 ($2,760) foldable phone after reviewers discovered problems with its display, dealing a setback to Samsung and its efforts to showcase its innovation.

"If we do not hear from you and we have not shipped by May 31st, your order will be cancelled automatically," the South Korean tech giant's US subsidiary told Galaxy Fold pre-order customers in an email late on Monday, which was confirmed by a Samsung spokeswoman.

The Galaxy Fold was meant to go on sale on April 26 in the United States. An Australian date and price was never confirmed, although Samsung did originally indicate the Fold would come to the country some time after the US release.