Accident Compensation Corporation board chairman John Judge warns the ACC scheme will be unsustainable in the next five years if costs are not cut and $2 billion in savings must be found.
The corporation on Friday reported an annual loss of $4.8 billion for the past financial year. In the previous year, it lost $2.4 billion.
The ACC scheme's liability, which involves the future cost of existing claims, has grown by $4.8 billion in the year to June and now stands at $23.8 billion.
Mr Judge told Checkpoint on Friday the corporation has just $11 billion to cover those costs.
He said the gap between available funds and liability will grow to about $30 billion in the next five years unless ACC changes its focus to get people off the scheme faster.
Mr Judge said ACC will get tougher with people on the scheme to reduce their time in rehabilitation, but they will not find it harder to qualify for support.
Costs to do with surgeries, therapies, scans and other necessities must also be cut, he warned.
Significant changes needed - minister
ACC Minister Nick Smith says the corporation's financial position leaves it in a perilous state and the Government has a number of decisions to make regarding ACC levies.
He says those decisions will be weighed against how much it pulls back on some of the unfunded extensions to the scheme put in place by the previous Labour-led Government.
Dr Smith says significant changes are needed to ensure that ACC becomes a financially sustainable, no-fault accident insurance scheme.
Earlier this year, the minister made sweeping changes to the ACC board, saying his new appointments had more investment and financial expertise.
The Labour Party has in the past accused the National Government of using shonky figures to create an impression of crisis which Labour says is not accurate.
