(Read Below) This is not true, it has been confirmed by the two banks that there have been no military or police in the bank other than to do normal transactions. So the only indication as mentioned below is some poor officer going about his normal day and doing a bit of banking..
From Raw blog site
There are indications that all commercial banks will close following the coup at Reserve Bank of Fiji earlier today.
Our sources also report that plain clothed military police have entered all the main Suva branches of ANZ, Westpac and Colonial Bank to watch the activities at the banks.