That buffer is roughly $14b – a sum of money yet to be allocated from the Government's $50b Covid-19 fund, announced at the budget.
On Budget day that figure was $17b but on July 6, the Government allocated a further $3b to a range of Covid-19 initiatives.
This included $50 million for additional PPE, $14.5m for boosting Healthline's funding and $710m for "significant investment" in the Three Waters Infrastructure.
New documents, released by the Government this morning, reveal a variety of government ministers' lobbied Robertson to spend more than $23b of the leftover $17b.
He whittled that down to just $3b.
In a press release, unrelated to this specific Treasury paper, Robertson made clear the Government's approach to the spending was "careful economic management".
"This is about getting the balance right between keeping debt under control while properly funding services like health and supporting businesses to respond to this 1-in-100 year shock."
The Treasury report revealed that ministers submitted 78 "unavoidable cost and revenue pressure initiatives" they wanted funded through the leftover $17b.
But the summary of initiatives, which details how much was spent on which projects, shows 54 initiatives were funded.
The Treasury report does not say which projects were not given the green light.
But it's likely they would have come with a hefty price tag, given the difference in the $23b pitched and the $3b approved by Robertson.
On June 4, Robertson wrote to all Ministers asking them to send him their Covid-19 related funding requests within six weeks.
To be in scope for the funding, Robertson said their pitch must be for "an unavoidable cost or revenue pressure initiative".
That initiative had to demonstrate increased costs or reduction of revenue that was "urgent and directly related to Covid-19".
In addition to this, the minister had to show that costs could not be met from budgets without staff redundancies.
