Fiji's Meteorological Service has confirmed there are two tropical depression systems which are likely to merge and form into a cyclone.
Director Alipate Waqaicelua says the first system will come over Fiji from Tuesday night before being joined by a second system in the coming days, with wild weather set to continue over the weekend.
Water levels in rivers are being monitored for any signs of flooding.
Earlier, forecasters warned a tropical depression moving towards Fiji from Vanuatu could develop into a category one or category two tropical cyclone by Thursday.
"At this stage we can be reasonably confident we are not looking at a category five tropical cyclone," Mr Waqaicelua said.
"This is a category one or worse category two cyclone, but at the same time we are very mindful that it's the rains and the winds associated with this and together with the associated floods that can be quite damaging to the country."
Mr Waqaicelua says he is not expecting any damage to houses if correct precautions are taken, but banana crops may be damaged.
"We're looking at rain, strong winds and possibly a tropical cyclone with cyclonic winds as well as damaging heavy swells, with flooding," he said.
"So we are a looking at a whole range of issues to affect Fiji for the rest of the week and the weekend."
© ABC 2014
19:57 EDT The damage bill from a supercell storm that hit south-east Queensland yesterday afternoon with cyclonic winds and softball-sized hail could reach $150 million, Queensland Premier Campbell Newman says.