( CNN ) -- Searing temperatures in Melbourne have disrupted play at the Australian Open , where tennis players have been struggling in the heat in recent days . Organizers of the grand slam event said Thursday that they had introduced an `` extreme heat policy '' after temperatures rose above 40 degrees Celsius ( 104 degrees Fahrenheit ) . That means that matches already under way on court will be suspended at the end of the set being played . The organizers said the roofs would be closed at the Rod Laver Arena and the Hisense Arena so that players could continue their matches on those courts . But new matches wo n't start on outdoor courts `` until the temperature falls back down to a temperature deemed fit for play by the tournament director , '' the statement on the website said . The severe heat at Melbourne Park this week has already caused problems for players . Canadian Frank Dancevic fainted during his defeat in the first round on Tuesday . He said he thought the conditions were `` inhumane . '' On the same day , China 's Peng Shuai blamed the heat after she cramped up and vomited during her defeat to Kurumi Nara of Japan . And it 's not just players who have succumbed to the elements . One of the ball boys fainted during 11th-seed Milos Raonic 's four-set victory over Spain 's Daniel Gimeno-Traver on Tuesday . Some players worried . Several players have voiced concerns about the conditions . `` Whether it 's safe or not , I do n't know . You 've just got to be very careful these days , '' Britain 's Andy Murray , who has been a finalist in Melbourne in three of the last four years , said Tuesday . `` There 's been some issues in other sports with , you know , players having heart attacks . '' Women 's world No . 1 Serena Williams said Wednesday the fear of dehydration was giving her sleepless nights . But 17-time Grand Slam winner Roger Federer appeared unfazed . `` Just deal with it , because it 's the same for both ( players ) , '' he said Tuesday after defeating spirited Australian James Duckworth in the first round . Before Thursday , tournament officials had already introduced heat-related measures for matches in the women 's draw , allowing for an extended break between the second and third sets . The Australian Bureau of Meteorology forecasts maximum temperatures in Melbourne of 44 degrees Celsius ( 111 degrees Fahrenheit ) for Thursday and Friday . Temperatures are then expected to drop into the low 20s ( high 60s and low 70s in degrees Fahrenheit ) starting Saturday . The heat wave currently blasting southern Australia comes after the country experienced its hottest year on record in 2013 , according to the Bureau of Meteorology . CNN 's Elizabeth Joseph and Steve Almasy contributed to this report .
Tennis officials issue an ` ` extreme heat policy '' after temperatures top 30 Celsius . The policy suspends current matches at the end of the set being played . It also stops new matches on outdoor courts until temperatures decline . The heat has already affected some players in matches this week .