South Korea put its latest high-tech weaponry on show Tuesday as tensions rise in the region following Pyongyang's test-firing of three missiles this week.

North Korea fired the mid-range missiles on Monday, triggering condemnation from the US and Japan while winning praise from leader Kim Jong-Un who hailed their performance as "perfect".

Pyongyang has conducted a fourth nuclear test and a series of missile tests this year in defiance of UN sanctions, prompting Seoul to announce plans to deploy a US anti-missile system to counter such threats.

The biennial DX Korea exhibition organised by the South Korean government in Seoul involves around 250 companies, many of them local.

Korean arms manufacturers displayed the K9 self-propelled howitzer, the Surion helicopter, the K2 main battle tank and other military equipment during a press preview.

Exhibitors also staged a live-fire show at a shooting range outside Pocheon city near the border with North Korea to display their artillery, mechanised infantry fighting vehicles and missiles.

Potential buyers from 25 countries have been invited to the exhibition which will run from Wednesday until Saturday, organisers said.

Apart from South Korean companies, 80 foreign firms from the US, Germany and Israel are also taking part in the exhibition.

South Korea's arms exports fell from $3.6 billion in 2014 to $3.4 billion last year.