FIFA has announced that the use of a fourth substitute during extra-time will be tested at this year's Olympic Games and Club World Cup.

The International Football Association Board (IFAB) agreed at their latest meeting earlier this month to allow for the experimentation of an additional sub during matches that extend beyond the allotted 90 minutes.

"The FIFA Executive Committee agreed for such experiments to be conducted this year at the Olympic Football Tournaments, the FIFA U-20 Women's World Cup Papua New Guinea and the FIFA Club World Cup Japan," football's governing body confirmed via a release on Friday.

FIFA also confirmed they have appealed to the Greek authorities, along with UEFA, to reverse the decision to postpone the Greek Cup final.

The government had cancelled upcoming matches indefinitely after crowd violence in the semi-final between PAOK and Olympiacos forced the first leg to be abandoned.

FIFA also used Friday's statement to underline their commitment to implementing reforms to the organisation, which had been approved at the electoral congress on February 26.

These include a new recruitment policy to "focus on diversity and gender equality", and adjusted financial targets.

"I've been tremendously energised by what I have seen, heard and experienced over the last 21 days," said president Gianni Infantino.

"Football is at the heart of FIFA and this is reflected in all of our priorities set for the coming months. The Executive Committee decisions this week ensure that we now move from words to actions.

"I am sure that with the measures in place, and those to be rolled out in the near-term, we can not only restore FIFA's image but also ensure that the world will be proud of FIFA."