The Turnbull government has quietly banked revenue worth nearly $3 billion from a new economic policy expected to be announced this year, as it also moves to demand more tax from multinational tech giants and popular digital players like Uber.

Budget papers show the Coalition is relying on a revenue leap worth $1.2 billion next year financial year, $909 million in 2019-20 and $764 million the year after that, bringing the mysterious revenue surge to a combined $2.77 billion.

The total figure, listed under a "decisions taken but not yet announced" column, is worth about three times as much as what was included in last year's budget, suggesting a substantial new policy has been included in the bottom line and will be made public shortly.

Unannounced revenue measures in Treasurer Scott Morrison's first budget were worth just $6.9 million.

The provision has been described as unusual by former senior finance officials, who believe it is consistent with a pattern of closing a tax loophole.