The decision was announced following a meeting of the International Olympic Committee's ruling Executive Board here today. 

Lausanne 2020 will also feature new disciplines seeking to reflect the twin goals of innovation and gender equality.

These include a mixed-nationality 3x3 ice hockey tournament, a women’s doubles competition in luge and the introduction of a women’s Nordic combined ski event. 

Additional venues are not expected to be required.

"The confirmed event programme means full gender balance the first time at a Winter Olympic event, with the highest number of women’s events and women ever competing at the Winter YOG," said an IOC statement.

"This gender equality reflects what has been previously achieved for the Youth Olympic Games Buenos Aires 2018 and the significant steps announced last month in the programme for the Olympic Games Tokyo 2020."

Ski mountaineering involves climbing mountains either on skis or while carrying them, depending on the steepness of the ascent, before descending on skis. 

It will join the seven Winter Olympic sports of skiing, ice hockey, ice skating, curling, biathlon, luge and bobsleigh.

Individual, sprint and relay disciplines will be contested following a proposal by the Organising Committee.

The 3x3 version of ice hockey is more of a "pick up" and development version played on a smaller size rink in addition to the existing events.

Last month it was announced that 3x3 basketball had been added to the programme for Tokyo 2020. 

In total, there will be 81 events contested in Lausanne compared 70 at Lillehammer 2016.

A process is currently ongoing to consider wider reforms to the Youth Olympics after 2020.

A "two-wave" stay of athletes will also be pioneered at Lausanne 2020, giving "more young athletes the opportunity to have the Winter Youth Olympic experience". 

Athletes will be able to condense their length of stay, meaning no need for additional beds in the Youth Olympic Village. 

A total of 1,880 athletes are expected to compete here in the Swiss city.