A Swedish scout spied on their World Cup rivals South Korea using a high-tech telescope from a house overlooking their training ground, prompting an official apology from Sweden’s head coach.

South Korean manager Shin Tae-yong. Photo: Reuters

South Korea’s manager has now come up with an ingenious way of throwing any further spies off the scent, swapping his players’ training jersey numbers because “it's very difficult for westerners to distinguish between Asians.”

“We switched [jerseys] around because we didn’t want to show everything and to try to confuse them,” Shin Tae-yong added.

The South Korean manager's somewhat amusing explanation for the training ground ruse came as he shrugged off talk about Sweden's pre-game tactics being unsporting.

"All coaches probably feel their opponents are always spying on them. I think it's perfectly natural that we all try to get as much information on each other as we can,” he told a press conference on Sunday.

Sweden and South Korea will face each other in their opening World Cup fixture on Monday at 2pm.