BRAZZAVILLE - Voters in the tiny oil-exporting Central African state of Congo Republic headed to the polls to elect a new parliament in Sunday, with the ruling party of President Denis Sassou Nguesso and its allies seen holding the majority.

Opposition parties have complained about a lack of access to state media during campaigning and early voter turnout was thin, a Reuters reporter in the capital Brazzaville said.

The ruling Congolese Workers' Party (PCT) and a cluster of allied parties control all but a dozen of the nearly 140 seats in the lower house after the opposition boycotted the last poll in 2007, accusing the government of vote rigging.

Nguesso came to power in a 1997 coup and has won two elections since then, including a 2009 presidential vote marked by accusations of fraud. A constitutional limit on presidential terms mean he must step down in 2016, although some opposition groups believe the PCT and allies will seek to change that.

Under Nguesso's rule, Congo Republic has enjoyed a degree of stability since 1997. However in March around 200 people were killed in a blast sparked by a fire at an arms dump in Brazzaville filled with munitions left over from the civil war.

The former French colony is expecting oil production at around 288,000 barrels per day this year, worth $5 billion in revenue. The International Monetary Fund sees economic growth rising from 3.1 percent this year to over 5 percent in 2013.