I think this happened also in other countries.
It is quite strange that besides the Indonesians and Filipinos girls, East Asians eg the Japanese and chinese girls likes Bangladeshi men too...although they aren't construction workers in this instance. South Asian men from India, Pakistan,Bangladesh working in Japan, China Hk ,Taiwan and even Korea(who frown on inter-racial marriages) has no problems attracting the local woman. A friend's sister in Taiwan, quite a pretty chinese well educated lady married a bangladeshi teacher and converted to Islam. Another japanese colleague married an Indian men working in Tokyo and are deeply in love with him years after they married and had kids. She recalled Japanese man pales in comparison to Indian guys.
Locally, I also noticed local young esp chinese girls dating Indian guys(south Asians to be exact) and the numbers are increasing. This is esp prevalent in tertiary institutions. If one look around in the CBD district, one will see chinese girls going lunch with their Indian male colleagues while chinese guys goes lunch with their chinese guy friends. Our ministers of Indian descent mostly have chinese wives too . While stereotypes suggests the chinese looking down on these people, the chinese girls seems to be different, esp the well educated,sophiscated ones whom I think goes for charm, communication,sharing of similarities rather than skin colour.