UPDATED 10.31am: The Prime Minister's responding to claims by Labour that the Government is ripping off the small business sector with ACC levies.

An Infometrics report commissioned by Labour shows businesses are being overcharged by $350 million per year.

John Key told Newstalk ZB's Mike Hosking the rates are coming down.

"What we can afford to do is what we're doing at the moment at the pace we're doing it in terms of cuts, and there's more coming."

His calls come after ACC Minister Nikki Kaye said the government was taking a long term view on ACC levies.

"We ensure that there are levy reductions where we can, but we enable the scheme to be sustainable long term.

"So we'd rather withstand the shocks from the things that happen like discount rates."

Nikki Kaye says the numbers are out of date, and she's expecting some more accurate figures in the next month.

Group questions overcharged claim

A small business group isn't impressed by the prospect they may have been overcharged by ACC.

Labour says independent research shows the Government agency is charging $350 million more than it needs to every year.

Small Business Voice chief executive Max Whitehead says a lot of that money would be coming from businesses that need it.

He says a large proportion of small businesses operate from week-to-week, providing important services and employment.

Max Whitehead says any and all charges on small businesses need to be justified.

He says it's important the Government reviews all the services it charges small businesses for, including ACC.