South Korea's conservative ruling party changed its name on Thursday to try to shore up sagging support in a key election year, but sceptics called it a cosmetic measure which would fail to impress voters.

The Grand National Party (GNP) announced it had chosen 'Saenuri' (New World) as its new title from some 10,000 suggestions made on the Internet. Rejected ideas included 'New Hope Party' and 'One People's Party'.

"We will be reborn as an entirely new party. I believe that people will trust us again if we continue our reform efforts with firm determination," said interim party chief Park Geun-Hye, its likely presidential candidate.

The party now holds 166 of the 299 parliamentary seats along with the presidency. But it anticipates a struggle in the April general election and the presidential poll in December amid a sharp slide in voter confidence.

In a shock result, it lost the Seoul mayoralty last October to an opposition-backed left-leaning candidate. It is now trying to shed its image as a party for the rich and to move leftward.

A major bribery scandal involving the election of a party chief in 2008 dealt the embattled conservatives a further blow.

Surveys show the party's popularity waning because of growing discontent over social and economic inequality, and as economic growth slows.

The left-leaning opposition Democratic United Party (DUP) has an approval rating of 39.7 per cent against 29.1 per cent for the GNP, according to a survey by the Realmeter agency in late January.

As part of reform measures the then-GNP even debated - but decided against - dropping the word "conservative" from its platform.

But it overhauled policies to shift its focus from the free-market economy and pro-business growth to 'welfare state' and 'democratic economy', with the promise of more education and welfare benefits for the poor.

"It's a natural move given the widening income inequality in this country and raging global debates on the 99 percent versus 1 per cent amid the recession," said Lee Junhan, professor of politics at Incheon University.

"The issue of welfare will be the keyword in election campaigns this year," he told AFP.

South Korean parties have made a habit of renaming themselves in election years as they merge or split to win more votes.

The DUP - which also faces allegations of vote-buying at a party election - chose its current name last month after joining with major union leaders and other left-leaning groups. It was its third name change in eight years.

Many are sceptical about whether the former GNP's new name will pay off.

Its website has been flooded with hundreds of mocking name suggestions referring to the bribery scandal and other cases of alleged corruption.

"Apparently they think voters have no brains. Your fundamentals will never change just because you put new make-up on," said one commentary.

Lee said the name changes were a relic of decades of military-backed regimes, when political opponents were jailed or barred from politics. The nation achieved democracy in 1987.

"It was a survival tactic for opposition parties to quickly merge or split as their leaders were often absent under political repression," he said, calling the practice "one of the most backward traits" of the country's politics.

Chosun Ilbo newspaper, in a recent editorial, pointed out that parties habitually rename themselves 'whenever they feel cornered' even though their support base is unchanged.

"Instead of looking for a quick fix in a new name, the party (GNP) needs to show voters that it is undergoing a painful process of reforms," it said.