BANGKOK, Dec 19 (Reuters) - Thailand's cabinet has approved debt suspension for smaller businesses and support for retail debtors, the prime minister said on Tuesday, in the government's latest move to address the country's festering debt issues.

The programme is part of a plan to help the 10.3 million people who are struggling to service debt, a drag on Southeast Asia's second-largest economy, where household debt stood at 90.7% of gross domestic product at the end of the second quarter.

The government will also try to keep diesel prices at about 30 baht ($0.86) per litre and electricity bills at up to 4.2 baht per unit to help lower energy costs, Prime Minister Srettha Thavisin told reporters.

The diesel price cap would be for three months and supported by tax measures and the national oil fund, Energy Minister Pirapan Salirathavibhaga said.

New electricity bills would be decided in January, he added, but vulnerable groups will be offered the current rate of 3.99 baht per unit, he said.

Government subsidies have helped keep inflation low, with the headline inflation rate coming at -0.44% in November, the lowest in nearly three years.

($1 = 34.98 baht) (Reporting by Orathai Sriring and Satawasin Staporncharnchai; Editing by Kanupriya Kapoor, Martin Petty)