Trace of Indonesian chess player in Australia found in this chess column from The Canberra Times, 10 February 1971. The article titled "Crime and Punishment" wrote by George Stern highlight two chess games for its adventurous theme, the first game was Australian players John Alps vs Baker. Then the second game was Lajos Portisch vs Hamdan, from Indonesia. In this QGD game, Lajos Portisch simply get a nice mating pattern on King's side and the Indonesian player simply did not find the best defensive system against it. See this nice, rather instructive game by the Hungarian grandmaster.
The tournament in context was probably Australia Open 1971 held in Adelaide. The winner was Lajos Portisch by half point ahead Walter Browne. From the article the standing was:
Adelaide - Karlis Lidum Tournament / Australia Open 1971 (?)
1. Lajos Portisch
2-4 Walter Browne
5. Alexander Matanovic
Barber, Flatow, Fuller, Hay, Hamilton (Australia)