Wellington, Sept 3 NZPA - A smart card that subsidises healthy foods has been recommended by obesity researchers.

The system was proposed in research commissioned by the Ministry of Health, the New Zealand Herald reported.

One of those involved in the research, health economist Des O'Dea, told a Public Health Association conference in Dunedin yesterday that for some families it was a struggle to buy healthy food.

"When you are short of cash, you often go for the high-energy foods -- junk foods."

The research, financed by the ministry and the Health Research Council, considered removing GST from healthy food but preferred the electronic smart card which could be targeted at low income earners.

Mr O'Dea, from Otago University's Wellington campus, estimated this would cost the Government around $100,000 a year.

Pensioners should be excluded because they had not been found to experience food insecurity, he said.