Research found 46% of those with gambling harms were hesitant to ask for help, with 17% believing their gambling was not harmful, and 27% saying they were likely to experience stigma or shame.
The inaugural Treatment Needs and Gap Analysis Report was carried out by researchers including the National Centre for Social Research.
It included a population level survey by YouGov, with more than 12,000 adults between September and October last year taking part.
The Problem Gambling Severity Index (PGSI) was used to determine the risk of a gambler. Research found 13% of adults scored one or higher on the scale, with 3% defined as a problem gambler, scoring 8+.
Only 17% of those showing any level of harm used some type of treatment or support in the past year, while women, those from ethnic minority (BAME) communities and from lower socioeconomic backgrounds may not be having their support needs adequately met.
Recommendations from the research included making sure services are tailored for the aforementioned groups less likely to have access to it, and continuing education programmes to increase gambling addiction awareness.
GambleAware CEO Marc Etches said: "This research has shown there is a clear need to further strengthen and improve the existing treatment and support on offer, to develop routes into treatment and reduce barriers to accessing help."