Thailand's private consumption contracted in December and investment stalled, the latest evidence that the country's growth engines remain shaky and the economy is not back on track.

Taken together with weak output and import figures released during the week, the data show the military junta was unable to make much headway in reviving the economy even after seizing power in May to end months of paralyzing political unrest.

The junta has pledged to ramp up infrastructure this year, but economists say the full benefits of such projects may only start to be felt late in 2015, while years of political uncertainty could be eroding the country's competitiveness.

The central bank said on Friday its index of private consumption, which accounts for half of the economy, fell 0.7 percent in December. The last time it rose was in September.

An index of private investment gained 0.1 percent from November, a month in which it climbed a revised 2.2 percent.

"Despite lower cost of living and production cost benefits from falling oil prices, private spending softened as consumers remained cautious and businesses awaited economic recovery and clarity on government's infrastructure investment," the Bank of Thailand (BOT) said in a statement.

HOUSEHOLDS 'CAUTIOUS'

Noting that recovery remained "slow" and consumption declined, it said "benefits from lower global oil prices have not passed on to private consumption as households remained cautious in spending given elevated debt levels and low farm prices."

Although the army coup restored some confidence, efforts to get the economy growing have been stymied as exports remain sluggish, domestic demand is still subdued and government spending has not risen sharply.

"The economy has shown a recovery, but at a very slow pace," said Thammarat Kittisiripat, economist with TMB Bank in Bangkok.

Southeast Asia's second-largest economy grew only 0.2 percent in the first nine months of 2014, and the government sees growth of less than 1 percent for the full year. Official data will be released on Feb. 16.

LOW BASE ON GROWTH

On Friday, the BOT said the economy in October-December grew more than 2 percent for a year earlier. But the comparison base is low, because the annual pace in the last quarter of 2013 - when anti-government protests began - was 0.6 percent.

The central bank has forecast the economy will grow 4 percent this year, counting on government spending and investment, and benefiting from 2014's low base.

The BOT on Friday said exports in December rose 2.3 percent from a year earlier while imports fell 7.9 percent. On Tuesday, the Commerce Ministry gave its figures, of a 1.9 percent gain for exports and a 8.74 percent fall for imports.

The central bank and ministry agree that exports - equal to more than 60 percent of GDP - fell in 2014. The BOT expects them to rise only 1 percent this year, due to weak global demand and falling commodity prices.

Factory output slipped 4.6 percent last year, after declining for the 21st straight month in December. The government predicts a 3-4 percent rise this year.

Fears of a resurgence of political tensions resurfaced this month after the country's junta-appointed assembly impeached the ousted prime minister and banned her from politics for five years, though there have been no reports of fresh confrontations.