SEOUL (AFP) - This week's general election in South Korea is expected to feature a new breed of "angry young voter", - millennials frustrated with record-high unemployment and widening inequality in career prospects.

The April 13 ballot for the 300-seat national assembly has been touted as a referendum on the economic policies of the ruling conservative Saenuri Party, and President Park Geun Hye, who has less than two years left of her single five-year term.

Polls suggest the Saenuri, popular with older voters, will retain the simple parliamentary majority it won in 2012, especially with rifts between opposition parties threatening to split the liberal vote.

But surveys also point to a possible new variable made up of members of what has become known as the "three-no generation" - no job, no home and no marriage prospects.

Growth in Asia's fourth-largest economy has stuttered in recent years, in line with a global slowdown and increasing competition in key export markets.

As cash-strapped businesses have scaled down or stopped hiring altogether, the jobless rate for those under 30 has reached a record high of 12.5 per cent - compared to a national average of 4.9 per cent.

"There is so much anger in us right now," said Mr Kim Min Jun, a 24-year-old college senior in Seoul.

Mr Kim said most of his friends at the elite Sogang University had become "automatically jobless" upon graduation, with many applying for 40 to 50 jobs with no success.

For those lucky enough to find work, buying a home in the capital Seoul - where most of the decent jobs are - is largely a pipe dream given the surge in property prices in recent years.

With interest rates at a record low, household debt on a national level now stands at an unprecedented US$1 trillion (S$1.35 trillion).

"For now, voting seems to be the only way left to draw politicians' attention to this grim reality," said Mr Kim.

"Many say the April 13 should be a judgement day (for the ruling party) for making our society and our lives so miserable," he added.

A recent poll by Gallup Korea showed that 17 per cent of voters under 30 supported Saenuri, with nearly 40 per cent for the different liberal opposition parties.

Others have yet to decide, but there is a new determination to cast ballots among an age segment that is not particularly known for turning out on polling day.

In 2012, only about 40 per cent of young people voted, well below the national average of 54 per cent and the 68 per cent turnout among those aged over 60.

But answering a recent official election committee survey, more than 55 per cent of young voters said they would "definitely" vote" in Wednesday's election, compared to 36 per cent a year ago.

Prof Lee Chung Hee, a politics professor at Hankuk University of Foreign Studies, said the frustration among millennials reflected a major socioeconomic shift.

"South Koreans used to have this strong belief that no matter how bleak the situation, you could get a good job and prosper by working hard enough and trying hard enough," Prof Lee said.

"Now, young people realise that trying hard on your own is simply not good enough," Prof Lee added.

South Korea's extraordinary transformation from war-torn backwater to economic powerhouse through the 1970s and 90s brought new levels of prosperity that were initially shared quite equally.

But income inequality has widened dramatically in the last decade and a half, and there is growing anger - especially among those in their 20s - that scarce, high-paying jobs are all too often grabbed by children of well-connected, well-heeled parents.

The top 10 per cent of earners account for nearly a half of overall income - the highest ratio in Asia - according to a study by the International Monetary Fund published last month.

That disparity has given rise to terms like "dirt spoon" for those stuck in low-paid jobs with bleak prospects, compared to someone with inherited wealth and a fast track to gainful employment who grew up with a "golden spoon" in the mouth.

The problem facing the angry young voters who want to register their grievances at the ballot box is just who to vote for.

While Ms Park and her Saenuri party have been criticised for their handling of the economy, the opposition parties are not seen as having much to offer in the way of alternatives.

"We often joke that if we combine all the jobs the political parties promised to create for the youth, it would be far more than South Korea's entire population," said Mr Kim Min Su, a Seoul labour activist running a campaign to improve youth turnout.