The latest polls put Korea's ruling and main opposition parties in a dead heat, just one month ahead of the April general election.

In a survey by news channel YTN, the ruling Saenuri Party appeared to have a slight lead at 45.6 percent, while the opposition Democratic United Party was supported by 42.6 percent.

But public broadcaster KBS' survey of 1,000 people showed a slightly different picture, with a little over 35 percent of respondents saying they would vote for DUP candidates compared with 34 percent for the ruling party.

Asked about a leftwing coalition between the DUP and the United Progressive Party, close to 43 percent thought it was a good idea, as opposed to 37 percent who did not.