The Maritime and Port Authority (MPA) says the incremental concessionary rates of SGD0.50 ($0.35) per day for OSVs would be extended from the current 90 days to 180 days.

The Singapore regulatory body said the new extension period would last for twelve months starting 1 November 2015.

"The rates will be applicable to OSVs approved by MPA that do not carry out cargo operations, calling at MPA designated offshore marine locations and/or specific anchorages in port," MPA said in a port marine circular.