Taiwanese health authorities issued a travel alert to cover all of South Korea late on Tuesday, widening its caution on travel to the country stricken with Middle East Respiratory Syndrome (MERS) where at least seven have died.

The alert issued by Taiwan's Centers for Disease Control also recommended that Taiwanese avoid medical institutions when travelling in South Korea.

Earlier, Taiwan had issued its travel alert only for Seoul, while putting the rest of the country on a less serious "watch" level.

Taiwan has a three-level warning system for travel to epidemic areas. The first level is called "watch" and reminds travellers to take general precautions in line with local area measures.

The second level is "alert" where authorities issue stronger precautionary measures for travellers. The most serious is "warning" which recommends against non-essential travel to an epidemic stricken area.