The England international and Premier League ace has long been tracked by Jose Mourinho’s side.
And the 24-year-old was targeted last summer when United were looking to bolster their midfield options.
Mourinho is ready to prioritise additions in the middle of the park again at the end of the season.
With a replacement needed for Michael Carrick, Dier remains a key target, but United must convince Spurs to sell.
According to TransferMarketWeb, the Red Devils are looking to re-open talks with Tottenham.
Chairman Daniel Levy has held the stance that Dier is a player who is not up for sale.
However, United appear ready to test Spurs’ resolve over the versatile holding midfielder.
TransferMarketWeb add an opening bid of £55m may get negotiations started between the two clubs.
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Dier would certainly strengthen Mourinho’s midfield options and offer cover in defence too.
Whether or not Tottenham can be persuaded to let him go, though, is another matter.
Dier is currently tied down on a contract until 2021.
And Spurs do not intend to lose any star players, especially ahead of their stadium move this summer.