A huge monetary stimulus package to be unleashed by the Bank of Japan this week is a welcome step in supporting growth in the world economy, the managing director of the International Monetary Fund (IMF) said on Sunday.

"Monetary policies - including unconventional measures -- have helped prop up the advanced economies, and in turn, global growth," Christine Lagarde told a forum in south China.

"The reforms just announced by the Bank of Japan are another welcome step in this direction."

(Reporting by Koh Gui Qing; Editing by Benjamin Kang Lim and Robert Birsel)