A weakened Cyclone Evan is expected to hit New Zealand at the weekend.
The MetService says the tropical cyclone which has devastated Fiji and claimed lives in Samoa could bring heavy rain and flooding in some areas, and strong gale force winds.
A duty forecaster says it will be probably weaken as it moves south, and be less destructive than when it hit the Pacific nations with wind speeds exceeding 200km per hour.
Fijian authorities are tackling a number of problems after being battered by Cyclone Evan.
The centre of Nadi, the country's tourism hub, has been shut down to prevent looters from raiding cyclone-damaged shops. The city went into lockdown on Wednesday afternoon after 19 people were earlier caught stealing from shops in nearby Lautoka.
Government agencies are now focusing on restoring power and handing out water purification tablets in the hope of avoiding a wide-spread outbreak of water-borne illnesses. Residents have been warned to be cautious in case storm water has contaminated drinking water.
People planning to travel to Fiji are being urged to check with their travel agents first.
NZ gives more aid
The New Zealand Government is giving Fiji and Samoa another $2 million each to help the Pacific nations recover from a destructive cyclone.
Five people were killed when Cyclone Evan slammed into Samoa last week, wrecking buildings, destroying crops and causing rivers to flood.
The storm went on to pound Fiji for more than 12 hours on Monday, destroying homes and hitting the communication network, power and water supplies. Western parts of the main island Viti Levu bore the brunt of the category four storm.
New Zealand had already committed $600,000 to Samoa and $400,000 to Fiji and is now giving each country a further $2 million.
Foreign Affairs Minister Murray McCully says that will ensure neither nation faces any financial constraints in the coming days.
Australia is giving Fiji and Samoa an initial $A1 million worth of emergency assistance each.
Food shortages predicted
The United Nations Childrens' Fund says it's working with the governments of Samoa and Fiji to keep children safe in the wake of Cyclone Evan.
UNICEF says water-borne diseases such as diarrhoea, leptospirosis and typhoid pose significant threats to children.
About 63,000 sachets of oral rehydration salts are being provided to Fiji's Ministry of Health to prevent dehydration from diarrhoea, and 5000 doses of tetanus toxoid vaccine to Samoa.
UNICEF NZ has launched an emergency appeal.
Aid agency Oxfam is predicting that severe damage to crops in Samoa from Cyclone Evan will mean food shortages.
Oxfam spokesperson Andy Thomson told Radio New Zealand's Morning Report programme there has been major damage to plantations in most areas of Samoa and while there is enough food for now, as time goes on there will be shortages.
He said Apia and south west Upolu have been hit the hardest, with about 500 houses destroyed.
http://www.radionz.co.nz/national/programmes/morningreport/audio/2541981/oxfam-preparing-for-long-term-recovery-in-samoa.asx Listen to Andy Thompson on Morning Report
Residents allowed home
The storm caused widespread damage in the cities of Nadi and Lautoka.
Some 8500 residents in Fiji who have sheltered in evacuation centres for two nights have been given the all clear to return home, but many houses have damaged roofs or are considered uninhabitable.
Fiji Red Cross Director General Filipe Nainoca said 600 houses in Lautoka have lost roofs. The organisation hoped to help residents with roofing damage on Wednesday.
Power and communication services remain affected throughout the country, and it's not yet known when they'll be restored.
New Zealand's Ministry of Foreign Affairs and Trade has urged the 500 New Zealanders in Fiji to abide by the country's State of Disaster guidelines.
Auckland to help
Auckland mayor Len Brown is to meet Pacific community leaders and government agencies to co-ordinate the city's efforts to help Samoa and Fiji recover from Cyclone Evan.
Mr Brown said Friday's meeting would focus on Samoa's immediate needs, which are likely to be food, clothing and building materials. Auckland Council will also look at relief funding and help to repair roads and water supplies.
The council's Pacific Peoples Advisory Panel chairman Uesifili Unasa said the council could also set up collection points for relief supplies and instruct its ports company to waive fees for shipping them to the islands.