Ukraine opposition leader Viktor Yushchenko has won the re-run of Sunday's presidential election in Ukraine, reports said.

Yushchenko won 54.08 per cent of the vote compared to 42.13 per cent for his rival, pro-Russian Prime Minister Viktor Yanukovich, based on reporting from 90.03 per cent of the country's precincts.

Now even if Yanukovich were to win every remaining untallied ballot he would not be able to beat Yushchenko.

The original vote, won by Yanukovich last month, was annulled due to widespread fraud.

Sunday's re-run was monitored by 12,000 international observers.