Australia have the highest rating of 133 since the new system of calculation was introduced in June, 2003, and can jump to 138 if Ricky Ponting's men swamp England 5-0 in the ongoing Ashes series, an ICC release said.
Number two England and number three India also improved their ratings in the annual update carried out on Tuesday which cancels out Test series played before August 1, 2002.
England go up three points to 114, but if they were to lose to Australia by 4-1 or 5-0, it would fall back to 111, the release said.
India, who lost three away series in Sri Lanka, South Africa and the West Indies between August 1, 2001 and July 31, 2002, benefit by four points because of the update and takes its rating to 111.
Sri Lanka slip to sixth place from number four and Pakistan slump to seven from five, as South Africa climb to four and New Zealand to five.