Up to £100m in council tax benefits goes unclaimed in Wales every year, says the assembly government.
Pensioners are among those not claiming benefits
Local Government Minister Dr Brian Gibbons has announced £3m extra funding for awareness campaigns, targeting the elderly and couples with children.
It is believed these groups are less likely to claim if they are homeowners.
Dr Gibbons also wants research on the system for claiming benefit, which he said could be seen as "complex, intrusive and not worth the effort."
Age Concern Cymru said up to 117,000 pensioners were living in poverty but urged them not to "suffer in silence".
A three-year funding package worth £1m a year is due to be spent to help more people claim benefits they are due.
Official figures show 46% of pensioners in Wales and 44% of couples with children are paying out much more than they need to in council tax
Three-quarters of those missing out on council tax benefits are homeowners rather than tenants.
Dr Gibbons made the announcement at a conference on Thursday in Llandrindod Wells, Powys.
The extra funding will aim to help local authorities widen the focus of their take-up campaigns to families with children as well as pensioners.
A working group will be formed to research the obstacles people face to claiming benefits.
Dr Gibbons said there were a range of reasons why people did not claim, from lack of knowledge to the process of claiming being seen as too complex.
Up to 28% of Welsh children live in poverty, say campaigners
He also called for changes in the benefits system at a UK level to ensure more automatic entitlements as well as increases in the earnings and savings thresholds.
His speech to an audience of benefits officers from across Wales stressed the need for partnership with the voluntary sector.
Age Concern Cymru said elderly people were trying to grapple with rising energy costs and council tax bills on limited fixed incomes.
Spokesman Michael Phillips said the amount of benefits which older people failed to claim, including pension credit and winter fuel allowances was nearer £210m.
Dr Brian Gibbons is to announce extra funding for take-up schemes
He said: "Many older people grew up at a time before the welfare state was created, where the culture was one of self-sufficiency and therefore they do not want to be seen as taking 'handouts'."
The Child Poverty Action Group said 28% of Welsh children still lived below the poverty line despite child poverty falling faster in Wales than the rest of the UK.
A spokesman said council tax benefit take-up was particularly low for owner-occupiers because it was administered alongside housing benefit and tended to be claimed at the same time.
"But with a third of children in poverty living in owner-occupier homes, plans to increase council tax benefit take-up for these families could help many poor children," he said.