Do they have any now? Well what would you think?... Yes
North Korean Infiltration Tunnels Under the DMZ
North Korea began digging tunnels under the DMZ at the same time that the South and the North first launched peace talks in 1974. According to intelligence analysis it is believed that North Korea began digging the tunnels after Kim Il-sung (North Korea's President) issued the September 25 Combat Readiness Order in 1971. In this order, he stressed the need to dig tunnels under the Demilitarized Zone, saying that one tunnel would be more effective than 10 atomic bombs and would thus be the best means to overwhelm the heavily fortified front.
Originally posted by 19KTankCommander
When I was stationed in South Korea, Camp Casey, we were always briefed on what the north was doing, during a 1 year period during 1992-1993 there were 5 tunnels that were found leading into south korea, big enough to drive a tractor trailer through.
Standard operating procedure was to flood the tunnels and eventual have them cave in on themselfs.
The dectection of these tunnels is an on going project for south korea all the time. With the newer technoligy I don't believe that ther really are any that are left.