South Korea announced controls on Friday on how the microblogging service Twitter can be used during elections, an issue that has some people calling for changes in the country's stringent election law.

The National Election Commission (NEC) said it is limiting the use of Twitter during the pre-election period under the election law, which bans the use of posters, printed materials, videos or similar mediums for campaigning until 180 days before a vote.

Any campaign-related use of Twitter before the 180-day period should be limited to exchanges of simple personal views on the candidates, the NEC said. Campaign messages carried during the period should indicate they are campaign advertisements.

The restrictions on campaign materials were originally introduced to limit the advantage of wealthy candidates but some lawmakers call them obsolete in the age of social networking.

It is an anachronism to apply the election law to Twitter, Democratic Party member of parliament Chung Dong-young said, calling the law unconstitutional and excessively restrictive.

The NEC has been under fire in previous polls for attempting to ban the use of video clips produced and shared among Web users. It has no plans to change its position unless the election law is revised, an official said.

South Korea will hold local elections on June 2.

(Reporting by Jack Kim; Editing by Jonathan Hopfner and Bill Tarrant)