The United States and Hong Kong shared the top slot as the world's most competitive economies in the newly released IMD 2011 World Competitiveness Rankings.

Last year's topnotcher, Singapore, went down to third place in the 2011 rankings, pulled down by rising property prices and food, energy and transport costs, according to the listing.

Australia also climbed down, from No. 5 last year to No. 9 this year, according to the listing by the Geneva-based IMD, also known as the International Institute for Management Development which is consistently top-ranked among business schools worldwide.

Aside from top three, other countries ranked higher than Australia are Sweden, Switzerland, Taiwan, Canada, and Qatar, which zoomed ahead from No. 15 last year to overtake Australia by a notch at No. 8.

Australia's drop in the rankings was a result of lower scores in "economic performance" (from No. 7 in 2010 to No. 13 in 2011), "government efficiency" (from No. 4 to No. 7), and "business efficiency" (from No. 5 to No. 7).

On the other hand, Australia's rating in "infrastructure" improved from No. 18 last year to No. 14 this year.

Completing the top ten list is Germany, which improved from No. 16 last year to No. 10 this year.

This year's edition of the IMD World Competitiveness Rankings includes, for the first time, a "Government Efficiency Gap" list which compares a country's government and business efficiency to determine, IMD says, "whether countries have 'the government they deserve'."

In more advanced economies-Japan, Belgium, Ireland, US, Germany, among others-the government lags behind business in efficiency, according to IMD.

In the IMD list, Brazil had the biggest gap at minus-26 points, based on a government efficiency ranking of 55 and business efficiency ranking of 29.

Japan, one of advanced economies where government efficiency lags that of business, had a score of minus-23.

The other advanced economies are: Belgium, minus-16; Ireland, minus-12; USA, minus-9; and Germany, minus-8.

The US, which had a negative government-business efficiency rating, was "rescued" in the overall competitiveness ranking by its business efficiency, the IMD explained.

Based on its calculations, a "sound balance" between government and business efficiency can be found in Hong Kong, Singapore, and Australia.

Australia's government efficiency was 7 in the rankings, while its business efficiency was also at 7.