"Some sealed roads might have to revert to metal only and some bridges needing repair or replacement may not be re-opened."
Mr Hughes said the review - which has come about through the Government policy statement on land transport - was also expected to re-classify secondary roads "and we can expect funding for them to drop".
"If council needs to increase its funding for road works then it will have to come from ratepayers."
He said the council would need to look at designated rural roads for heavy transport such as logging trucks.
Councillor Rob Vinsen said the "hypocrisy" of the review was huge.
"This is all predicated on the growth in Auckland and the Christchurch rebuild. We have to lobby on this," Mr Vinsen said.
Mayor Annette Main said council had been lobbying against cuts to funding and would continue to do so.
Ms Main said she hoped the recently announced regional growth strategy - which had Government's blessing - would help provide some influence.
"But the message is the same - the Government is talking regional growth but is not backing it up," she said.
Councillor Hamish McDouall said the funding change would leave a "huge hole" in local authority budgets.
"This draft doesn't reflect the views of most MPs in provincial New Zealand, it's being driven by urban MPs only worried about congestion in the major cities," Mr McDouall said.
Committee chair Councillor Ray Stevens said he was surprised the Government could not see the impact it would have outside the metropolitan areas.
"We're a primary producing city and as such are being penalised for having the raw commodity but not adding value to it," Mr Stevens said.
"It's another policy of having the poor subsidising the rich. We have road-user charges and fuel taxes that are paying for work outside of Wanganui. "
He said the NZTA will be reducing its financial assistance by 1 per cent a year for up to nine years,.
"This means in year one an additional $120,000 will have to be funded from rates to maintain current levels of service. By year nine $1.08 million in additional rates will be required. This will then enable $3 million of road maintenance and renewal work to be undertaken," he said.
Mr Stevens said another impact will come with the decision by NZTA to no longer use hotmix to re-surface state highways in the central region.
"This downgrade will start this financial year through SH1/SH3 at Bulls, where the road will be treated with a chip-seal coat. Wanganui will have this downgrade the following year when Great North Road, passing Virginia Lake, will be resurfaced with chips which are noisier and will not last as long."