Foreign Minister Murray McCully says there will be $NZ1.2 million ($A1.12 million) on top of the $NZ300,000 ($A281,160) already provided and further assistance will be considered.
A Royal New Zealand Air Force C130 Hercules on Monday delivered tarpaulins, water containers and medical supplies.
Disaster response specialists and Red Cross personnel were aboard the aircraft and are helping with the relief effort.
“New Zealand will consider a wider recovery package as the Solomon Islands undertake longer term reconstruction efforts,” McCully said.
“It’s clear the flooding caused significant damage in places to housing, power lines, roads and bridges.”
Prime Minister John Key earlier told reporters he had talked to his counterpart Gordon Darcy Lilo and had told him more help was on the way.
“I made it clear to him we would give the Solomons anything they require to get through this, we’re working closely with Australia,” Key said.
So far 21 people are known to have died in the Solomons.
Key says up to 60 have been seriously injured.
The Ministry of Foreign Affairs knows of 147 New Zealanders living in the Solomons but none have asked for help.