Instead, the smaller reductions would begin in April 2014.
Furthermore, Ms Moroney said that the Government was using the levies to create the impression that it was in surplus.
"Most New Zealanders want the surplus to be reached through a growing economy, not trumped-up ACC levies. It is an artificial surplus because the fund cannot be used for anything but ACC."
The corporation's reserves have grown to more than $20 billion since the Government changed its funding model to cover the life-long cost of injuries, instead of a "pay-as-you-go" system.
Finance Minister Bill English said the Government had not wanted to make levy cuts until ACC was performing well.
"We don't want volatility in the levies where you're putting them up and then down all the time. We believe now that the performance is sufficiently embedded that we can look at a track over the next four or five years of steadily reducing ACC.
"That should deliver some quite significant bonuses back to households and businesses and wage-earners."
Green Party ACC spokesman Kevin Hague argued that levy rates could remain volatile because the new funding model was vulnerable to changes in the global economy.
"These ridiculous pendulum swings reflect the fact that this model simply doesn't work," he said.
Mr English confirmed the Government was still aiming to have ACC fully funded by 2019. He was not willing to open the corporation up to competition because the insurance industry was preoccupied by work related to the Christchurch earthquakes.
He emphasised that the Government was not considering managing ACC like a state-owned enterprise.
ACC levies
2008/09
Employers and self-employed: $1.26 per $100 of earnings (average rate)
Wage and salary earners: $1.40 per $100 of earnings
2009/10
Employers and self-employed: $1.31
Wage and salary earners: $1.70
2010/11
Employers and self-employed: $1.47
Wage and salary earners: $2.00
2011/12
Employers and self-employed: $1.47
Wage and salary earners: $2.04
2012/13
Employers and self-employed: $1.15
Wage and salary earners: $1.70