Some of the most vulnerable people in society are not included in studies used to measure poverty, leaving an "incomplete picture" of the situation, the National Audit Office has warned.

In its assessment of government's efforts at addressing poverty, the NAO highlighted how some of the poorest people in society are excluded from EU statistics surveys.

People living in prisons, homes for the elderly, faith-based institutions, migrant centres and the homeless are all left out.

"In this respect, the NAO is of the understanding that current statistics do not provide a complete picture of poverty in Malta," it said in a report tabled in parliament on Tuesday.

Malta has made "substantial progress" in reducing the proportion of people at risk of poverty, based on these EU-standard statistics. 

But the under-representation of poverty was also "substantial", it said, because those people left out of studies have a higher poverty rate than the rest of the population.

The NAO said that during its assessment, it had spoken to NGOs which flagged their experiences of "peripheral poverty". 

On whether there has been progress to reduce poverty in Malta, a number of contributors noted that poverty persists and has increased throughout the years.

According to the report, NGO representatives noted that social problems were increasing, and that material deprivation was increasing among vulnerable groups, such as older people or those with mental health issues.

Some NGOs also mentioned there was an increase in homeless people living in non-residential properties like garages or sub-standard housing, and children wearing dirty or torn clothes and going to school with no lunch.

The NAO backed proposals put forward by stakeholders for a "a broader definition of poverty or for supplementary indicators, surveys and qualitative studies to more comprehensively measure the extent of poverty and assess progress registered".