The Finance Ministry has painted a rosy picture of private investment, forecasting 2020 growth of 4.6%, up from 2.7% predicted for this year.
Investment in the government's flagship Eastern Economic Corridor project, an increase in exports and 2020 fiscal budget disbursement set to kick off in February should all rally private investment, said Wuttipong Jittungsakul, deputy director-general of the Fiscal Policy Office (FPO).
For the nine months to September, private investment expanded by 3% from a year earlier.
The Finance Ministry's think tank forecasts the economy to expand by 2.8% this year and 3.3% the next. Among policymakers, the FPO's projection is more optimistic than that of the Bank of Thailand, which predicts 2.5% this year and 2.8% in 2020, and of the National Economic and Social Development Council, which sees 2.6% in 2019 and 2.7-3.7% in 2020.
Value-added tax (VAT) on domestic consumption grew by 2.2% for the first 11 months if extra items are stripped out of the calculation, Mr Wuttipong said. Overall VAT collection for the period fell by 2% year-on-year.
Domestic consumption improved in November as VAT on domestic consumption at constant prices rose by 3.7% from a year earlier, while the import volume of consumer products was up 1.3% year-on-year.
Domestic car sales shed 16.4% year-on-year, and the number of new registered motorcycles dipped 6.8% last month.
Investment indicated by the property transaction tax, cement sales, and the building and construction material price index in November remained dismal. Property transaction tax revenue fell by 6.3% year-on-year last month, while cement sales were down 2.2% and material prices slid 3.1%.
Net farmer income for the 11 months to November rose by 1.5% from a year earlier.
Exports are expected to be the main engine driving the economy to meet the FPO's forecast of 3.3% next year, Mr Wuttipong said.
"International trade should fare better next year [if trade tension eases between the US and China], but we need to monitor the situation," he said.
The FPO predicts Thailand's outbound shipments to reverse course and record growth of 2.6% in 2020 after a likely contraction of 2.5% this year.
In November, exports in dollar terms plunged 7.4% year-on-year.
The consumer confidence index for the first 11 months stood at 63.2, compared with 67.8 for the same period in 2018 and 64 in 2017.