At the top of Vietnam's Fansipan Mountain, throngs of giddy tourists wielding selfie sticks jostle for a photo op on the once-remote peak in the Sapa region, famed for its breathtaking views across undulating rice terraces.

Getting to the top traditionally takes a two-day trek, but these days most visitors opt for a 20-minute ride by cable car instead - the latest flashy tourist attraction to heighten concerns over rapid development destroying Sapa's natural beauty.

Known by some as the Tonkinese Alps, the former French outpost has seen a tourism boom in recent years with a new highway from the capital and hotels popping up at breakneck pace.