The event at the Sport Buyant Ukhaa Complex is one of two World Tournaments scheduled to be held prior to the Games - and offer wrestlers who have not yet secured their places another chance.

In Ulaanbaatar, the top three wrestlers in freestyle and Greco-Roman as well as the two finalists in the women’s events will secure Rio 2016 berths for their countries.

Competition begins tomorrow with all of the Greco-Roman categories before the women's action on Saturday (April 23).

Freestyle wrestling will then conclude the competition on Sunday (April 24).

In the Greco-Roman, defending 59 kilogram Olympic champion Hamid Soryan of Iran remains as the biggest name not to have qualified for Rio 2016.

He failed to progress through the Asian qualification tournament in Astana and the London 2012 gold medallist is listed as an alternate to Saman Abdouli in Ulaanbaatar.

Bulgaria's Ivo Angelov, a world champion at 60kg in 2013, has also entered, while Azerbaijan has a pair of world champions involved at 66kg - 2010 winner Hasan Aliyev and last year's champion Rasul Chunayev who is down as an alternate.

London 2012 bronze medalist Johan Magnus Euren of Sweden will compete at 130kg and Olympic silver medalist and 2014 world champion Arsen Julfalakyan of Armenia will be one to watch at 75kg.

In the women's competition most of the top names have already qualified, but American Helen Maroulis is the outstanding contender at 53kg.

The 55kg world champion has opted to drop down and is considered the favourite in the class.

Hungarian Marianna Sastin, a former world champion at 63kg, is in the field, while Ukraine's 2013 world champion Alina Makynia is a big name at 69kg.

Freestyle will see Turkey's European champion Soner Demirtas in the frame at 75kg as well, as Asian Games gold medallist Rashid Kurbanov of Uzbekistan.

Mongolia's own Dorjkhand Khuderbulga leads the charge at 97kg with 2015 Asian champion Aiall Lazarev of Kyrgyzstan a leading contender at 125kg.

A total of 252 berths in the Rio 2016 wrestling competition have already been allocated to 52 countries.

The top six in each of wrestling’s 18 Olympic Games categories secured 108 berths at September’s World Championships while another 144 were earned in continental qualifying held over the last two months.

The second world tournament in Istanbul is due to be held between May 6 and 8.