The warning and alert have been sparked by tropical depression TD04F that the service says may strengthen into a cyclone in the next 12 to 18 hours.
At 4am today, the depression was about 310km north east of Rotuma moving south east at 30km/h.
On this track, the system is expected to be located about 115km east-northeast of Rotuma at four o’clock this afternoon.
With wind speeds of about 55km/h and gusts up to 80km/h, the service said a gale warning was now in force for Rotuma while a strong wind warning remained in force for all land areas of Vanua Levu, Taveuni, Lau and the Lomaiviti Group, Kadavu, the Yasawa Group and Northern Viti Levu from Rakiraki to Tailevu North.
A heavy rain warning remains in force for Vanua Levu, Taveuni and nearby smaller islands, the eastern half of Viti Levu, Lau and the Lomaiviti Group.
SOURCE: RADIO NZ