Lost inTranslation

I'm studying in New Zealand at the moment and I have my wife and two young daughters here with me. Both of them are under 5 and are amazingly quick at picking up the English language. My wife and I are always encouraging them to build their language skills and at first, it seems, everything is fine. Then, one day I decided to play a little game with my eldest daughter. I would ask her "what is X in Bahasa Melayu?" where X can be anything. I was surprised to find out that she doesn't know many common Malay words such as gajah for elephant, numbers more than 5, kereta for car etc. Though it is funny when she gives gibberish-sounding answers, this worries me a lot.

When I was doing my bachelor's degree in UPM, I had many Chinese and Indian-Malaysian friends who couldn't read their ethnic script and sometimes not even speak fluently in their mother tounge. I have always told them that this shouldn't be so and that they should not lose their cultural identity. I took some Tamil language classes at UPM and actually can spell and write in Tamil better than many of my Indian friends (though I might not know what the words mean). As a Malay, I can read and write in Bahasa Melayu well, and thanks to my religious school days, I could read Jawi well too (Malay language written in Arabic/Persian script). My point is that I have always taken it for granted that my kids will not have a problem with their own mother tounge.

Apparently, this is not so. Staying in New Zealand, my daughters are in a totally immersive environment where English is spoken everywhere. The only time that they ever hear Malay spoken is at home, and even then, I noticed that they prefer to speak in English when playing together. I am somewhat relieved to know that we will be going back to Malaysia after I have graduated but what of the kids of those who have migrated here permanently? Will they, after several generations lose the ability to read and converse in Bahasa Melayu? Are the parents okay with this development? Or should there be some sort of formal Bahasa Melayu education here in New Zealand? If so, who should do it?