The promised spending includes free education - a signature promise of Solomon Islands Prime Minister Matthew Wale - security improvements and small grants tied to every electorate.
The pledges were revealed in a leaked WhatsApp message sent by Solomon Islands Deputy Prime Minister Francis Sade, who was forwarding an update from the Australian high commission to the Pacific nation.
The revelations come after a week of high drama in Solomon Islands politics - and a sliding doors moment for Canberra-Honiara relations - when a no-confidence motion in Mr Wale's leadership was tabled and withdrawn.
In the message, the commission, led by High Commissioner Jeffrey Roach, wrote it hoped "both countries can hold steady to seize this opportunity and lock this in ahead of the November budget session".
At the time of the message, Mr Wale still faced the motion of no confidence, which was made by one of his own ministers.
Mr Wale had travelled to Palau to participate in the Pacific Islands Forum only to swiftly travel home to ensure his coalition held strong.
In his own message, which appeared aimed at any wavering MPs in his coalition, Mr Sade asked them to "look at the bigger picture and weight the situation against the positive momentum we have built".
Australian Prime Minister Anthony Albanese is attempting to upgrade relations - and most importantly, security co-operation - in the region as Canberra vies with Beijing for influence in the Pacific.
Australia has already landed defence treaties with Papua New Guinea and Fiji in recent months.
Australia has also signed treaties with Tuvalu and Nauru under Mr Albanese, and, alongside Solomon Islands, is currently negotiating a fresh pact with Tonga.
Progress on enhancing ties with Honiara had been slow under previous leaders but fast-tracked since Mr Wale took power in May.
Those treaty talks have proved fruitful, according to the leaked messages, which were verified by Mr Sade.
Australia's pledges - totalling $985 million - include $142 million to fund free education, $48 million towards "visa improvements and security requests" and $95 million in grants.
Those grants are cleaved off per electorate as part of a "community partnerships" fund, which allows locals to apply for Australian aid to build small-scale infrastructure like halls, toilet blocks, water tanks and schools.
Aid distribution in this way ties Australia to on-the-ground outcomes in every part of Solomon Islands, and, Canberra hopes, compels support for the security treaty from each MP.
Some in Solomon Islands argue this is Australia effectively buying support for its security treaty, a characterisation Mr Sade rejects.
In a statement provided to AAP, the deputy prime minister said the messages were "a routine update" and "never intended for political expediency".
"If there is good progress that benefits our country, why should petty politics be used to disadvantage or undermine such welcoming news?" he said.
Pacific Minister Pat Conroy would not be drawn on the length or substance of the Australia-Solomon Islands talks.
"Negotiations are under way - consistent with all of Australia's bilateral treaty negotiations, we will not comment on the details of the negotiations until the treaty is signed," he said.
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