Malaysia moves weekend start for Johor state
3 January 2014 Last updated at 03:51 GMT
Malaysia's southern state of Johor has switched weekends to Friday and Saturday, so the state's Muslim majority can attend prayer on Fridays.
Private companies can choose whether to follow the switch or not, so officials say they don't expect it to affect the state's economy.
But Malaysians are divided on the issue - and it's worrying some foreign investors.
The BBC's Jennifer Pak reports.