Tens of millions of pounds are owed to the local authority in council tax and business rates.
The total outstanding debt owed to Bury Council for the last 20 years is nearly £20m.
Most of this total, £12.5m, is owed in council tax, while the remaining £7.1m is owed in business rates.
More than 96 per cent of council tax and business rates due to the council was collected last year.
But the council is still owed £5.7m from that year alone and, so far, it has spent more than half a million trying to recover that unpaid debt.
In the previous year, it had enforcement costs of £714,797.56 – the highest in the last two decades.
Deputy Conservative leader Nick Jones thinks more needs to be done to strengthen’s the borough’s collections.
He said: “The current administration constantly talk about cuts and austerity yet there is nearly six million pounds outstanding in council tax and business rates.
“The council is predicting another overspend thus the collection of arrears would go a long way to balancing the books.
“Each year council tax rises to bring in extra capital to pay for the services delivered yet we still have millions outstanding in council tax and business rates.
“The authority simply cannot afford to not collect all of its Council Tax and Business Rates.”
Cllr Jones said he hopes things will improve under Labour’s new leadership but he believes the “status quo” will continue.
Liberal Democrat councillor Steve Wright also took issue with the figures.
He described the council’s finances as being in a “perilous state” with spending being “propped up” by raiding reserves.
He said: “Every year we find out that Bury’s Labour administration is failing to deliver on previously agreed savings targets.
“To find out that so much money remains uncollected in council tax and business rates just goes to re-enforces this.
“We need strong management of the council’s finances if we are to make sure there are not further brutal cuts to local services.”
Bury Council said it takes collection of council tax and business rates extremely seriously.
It claims that its collection rates of more than 96 per cent are similar to those in most other local authorities.
Arrears go down every year because the council continues to collect outstanding debt beyond the end of each financial year.
At the end of the previous financial year, the council was owed £3.44m in council tax.
But 15 months later this came down to less than £2m, taking the collection rate for that year to 98 per cent.
A council spokesman said: “It is vital that everyone pays what they owe so that essential services can continue to be provided.
“We will continue to use all avenues available to us to recover taxes that are owed. We would also urge anyone who is in financial difficulties to contact us as soon as possible.”