By Colin Packham

SYDNEY (Reuters) - Elections on the tiny South Pacific island of Nauru were fair and transparent, the first international observers to monitor polls on the world's smallest republic in more than a decade said on Monday.

Nauru, thousands of kilometers northeast of Australia, has been criticized internationally for human rights violations, including high levels of violence against woman and children, and political instability, with four presidents since 2011.

But observers said the weekend election had surpassed their expectations.

"We have heard about the ongoing conflict, members of parliament being suspended and allegations from both the government and the opposition, so I was concerned," Anote Tong, former president of the Pacific island of Kiribati, who led a team of Commonwealth observers, told Reuters.

"But the elections were very fair, very transparent and quite professionally done. I think this election represents an opportunity for a fresh start for the nation," he said.

Last year, the United Nations Special Rapporteur on human rights urged Nauru to improve its standing in a range of areas including freedom of expression, the independence of the judiciary and crackdowns on media access.

Nauru's government rejected most of the U.N criticism.

The island also hosts a controversial detention center housing asylum seekers on behalf of Australia - its biggest foreign aid contributor. Under Australian law, anyone intercepted trying to reach its shores by boat is sent for processing offshore.

The detention center houses about 500 people and has been widely criticized by the United Nations and human rights agencies for harsh conditions and reports of systemic child abuse. There are also high rates of self-harm.

Political instability has also plagued Nauru, with reports of frequent government crackdowns on dissent.

There were 67 candidates vying for support from just under 8,000 registered voters for the 19 seats in Nauru's parliament.

Nauru President Baron Waqa was among those re-elected, the new Nauru Electoral Commission said.

(Reporting by Colin Packham; Editing by Paul Tait)