Venezuelans changed their Constitution on Sunday to allow President Hugo Chavez to rule South America's top oil exporter for as long as he wins elections, refreshing his mandate to push socialist policies even as global economic worries loom.

There may be possible consequences of the referendum vote.

New left-wing policy announcements can be expected. After Mr Chavez's last re-election victory in 2006, the former paratrooper radicalised his self-declared socialist revolution by nationalising the energy and telecoms industries.

Such grandiose moves are too expensive this time, but Chavez is likely to look for other ways to accelerate his goal of making Venezuela the standard bearer for socialism in Latin America. Possible policies include handing out more land to poor farmers and increasing the power of loyal grassroots groups that could undermine opposition politicians.

Mr Chavez now has the breathing space to make the economic decisions he deems necessary. But if oil prices do not recover he is set for a tough year anyway.

Crude prices are down two-thirds since July and Venezuela's economy is slowing after years of oil-funded growth. Many analysts predict a budget shortfall this year that will push Mr Chavez to devalue the fixed bolivar currency and cut spending.

He could choose to put off a devaluation, gambling that oil prices will recover this year. Alternatively, he could decide to devalue quickly to get the pain of the resulting inflation spike out the way before legislative elections in 2010.

The value of Venezuela's already battered sovereign debt could fall as investors worry that Mr Chavez will burn through international reserves to maintain social programs, although analysts say he is unlikely to default on loans.

The result of the vote is a huge blow to the opposition, which had hoped to consolidate its electoral gains of the last year and head toward the 2012 presidential election without having to contend with Mr Chavez, Venezuela's most popular politician.

The opposition is without a clear leader and will struggle to beat the charismatic leftist unless his popularity falls rapidly on economic woes.

Chavez has consolidated his position as the leader of Latin America's more radical left. However, his international reputation grew partly because of his vehement and often vulgar criticism of George W. Bush and his declared war on terror.

New US President Barack Obama is a less divisive figure and is generally popular in Latin America, making the Chavez brand of anti-Americanism less appealing.

In April, Mr Chavez and Mr Obama are both due to attend the Summit of the Americas in Trinidad, just off Venezuela's coast.

Low oil prices will also increase pressure to cut generous Venezuela's foreign aid to Cuba, Ecuador, Bolivia and Caribbean island nations.