The funds are an even split between concessional loan and grant which the ADB says will also help mitigate the economic impacts of the virus.
The Solomons' government says the funds will help tackle health and economic strains caused by the pandemic.
It will finance the training of frontline nurses and doctors to fight the virus, as well as the acquisition of personal protective equipment for medical staff.
Economic stimulus will go to the farming and fishing sectors, small businesses, and state owned enterprises including Soltuna and Solomon Airlines.
Protecting the livelihoods of the poor and vulnerable, especially women, will also be prioritised.
The Solomon Islands closed its border on 25 March as a response to the Covid-19 pandemic and the country has extended the shutdown until 25 July.
There are no confirmed cases of coronavirus in the country.
Further ADB boost for Tonga's response to Covid-19
Tonga's response efforts to the Covid-19 pandemic have been further boosted with a US$12.2 million grant from the Asian Development Bank.
In April, Tonga received a US$6m injection to fund logistics of locking down the border and providing relief for people and sectors directly affected by the pandemic.
This included the elderly, unemployed and vulnerable businesses such as tourism, retail, agriculture, and transport.
This week, the ADB released its latest assistance to support the government's long-term economic recovery.
Earlier, parliament unanimously passed a $US260-million national budget for the coming year with Tonga's biggest ever deficit of over $US26.4m.
An ADB economist, James Webb, said the bank's programme would help limit the adverse social and economic impacts stemming from the pandemic.
Mr Webb said the programme would also help build on previous policy-based operations to strengthen Tonga's macro-economic resilience.
Tonga is presently free of confirmed Covid-19 cases.