New Zealand was ranked the least-corrupt nation of 66 examined by the World Justice Project in its new Rule of Law Index, while the U.S. finished an unremarkable 17th.

The ranking is another feather in New Zealand’s cap, after the country tied for first with Denmark and Singapore in Transparency International’s 2010 Corruption Perceptions Index.

Although the TI index is older and covers more countries — 178 total – the WJP index has a larger sweep. Corruption was one of several factors the group considered, including limited government powers; order and security; fundamental rights; open government; regulatory enforcement; access to civil justice; effective criminal justice; and informal justice.

The results are based on about 1,000 assessments from members of the general public in each country, as well as contributions from local legal experts.

New Zealand topped the “absence of corruption” list and placed in the top five in the world in seven of the eight categories of the Index.

“Government agencies and courts in the country are efficient, transparent, and free of corruption,” the study said. “Fundamental rights are strongly protected. The judicial system is accessible, independent, free of corruption and effective.”

Looking at corruption alone, Sweden finished No. 2 behind New Zealand. Singapore was No. 3, Norway No. 4, Japan No. 5, Netherlands No. 6, Hong Kong No. 7, Austria No.8, Australia No. 9 and Estonia No. 10.

There was little disagreement between WJP’s corruption rankings and TI’s index, at least in rating the top-tier nations.

New Zealand, Sweden, Netherlands, Singapore, Norway and Australia figured into the top 10 in both; Japan, Hong Kong and Austria finished in the top 20 in the TI index. Estonia marked the only significant departure, ranking 26 on the TI index.

Cambodia finished last on WJP corruption list, near Pakistan, Cameroon, Kyrgyzstan, Liberia and Kenya.

The U.S., which ranked 20th on the TI index, its worst finish yet, scored generally high marks in the WJP index, though it failed to crack the top 10 in any category.

According to the study, the U.S. stood out for its “well-functioning system of checks and balances and for its good results in guaranteeing civil liberties among its people.”

But it’s highest ranking — No. 13 of 66 for order and security — was offset by its performance on access to civil justice (No. 21).

“Legal assistance is expensive or unavailable, and the gap between rich and poor individuals in terms of both actual use of and satisfaction with the civil courts system remains significant,” researchers concluded, adding that there is a perception here that “ethnic minorities and foreigners receive unequal treatment from the police and the courts.”