Singaporeans outraged by an electronics shop that left a Vietnamese tourist in tears after a phone-sale scam have raised thousands of dollars to compensate him, a crowdfunding site shows.

Factory worker Pham Van Thoai, 28, on Monday forked out $Sg950 ($A789) to buy a new iPhone 6 in the Sim Lim Square electronics mall, which has long been known to victimise tourists.

Factory worker Pham Van Thoai, 28, was made to beg for his money after being caught in a phone scam in Singapore. Credit:YouTube

But employees of the "Mobile Air" store refused to allow him to leave with the phone unless he paid an additional $Sg1500 in "warranty fees". He was eventually given a partial refund of $Sg400, with no phone in hand, after police intervention.

A video widely shared on social media showed Pham kneeling down and begging the shop owner and employees for his full cash payment while they laughed at him.