The move on Thursday came after Slovenian border officials said July saw the highest number of crossings in a month since the peak of the refugee crisis a few years ago when thousands of people fleeing war and poverty in their home countries tried to move up from the Balkans towards northern Europe.
Likar said the exact timeline and location for the erection of the fence would not be made public.
Broadcaster POP TV reported that work had begun on a 4km stretch between the villages of Zilje and Zunici, in southern Slovenia.
A Reuters news agency photographer close to the nearby village of Preloka saw construction work under way at the site.
Slovenia first began constructing a border fence during the refugee crisis of 2015, when in six months, about half a million people passed through the country.
It has already constructed about 180km of mostly barbed-wire fence, and once the new section is completed, the total length of fence will be 219km and cover almost a third of the Slovenian border with Croatia
Last month, Slovenia’s army announced that nearly three dozen troops will join the country’s police in patrolling borders in the southwest of the country. The army has taken part in border patrols alongside the country’s police since 2016.
The army said its soldiers would bring their equipment to help the police operate in the area of the coastal town of Koper, which is near the Croatian and Italian borders.
The government’s immigration policy has met little opposition in Slovenia, although some civil society groups have opposed building the fence.