WINDHOEK, Namibia (AP) _ Two days of voting ended Wednesday in an election almost certain to return to power the only ruling party Namibians have known in a decade of independence.

The southwest African country's biggest opposition party said it was already considering contesting the count, though final results aren't expected until Monday. Early results were expected Thursday.

``The whole system lends itself to rigging,'' said Nico Smit, spokesman for the opposition Democratic Turnhalle Alliance.

Opposition parties on Tuesday charged that the election was fraudulent because ink applied to voters' thumbs could easily be washed off, making it possible for people to vote more than once.

One man was arrested for trying to vote twice. But South African Judge Ismail Hussein, an election observer, said he saw nothing that undermined the vote's result and Elections Director Joram Rukambe said a new set of instructions had been issued to poll officials on how to use the ink.

Heavy rain in parts of the normally dry country hampered election officials, although voting generally went smoothly.

The percentage of the 878,000 registered voters who cast ballots was expected to be known Thursday once ballot boxes were collected from remote areas, said Electoral Commission spokesman Peter Mietzner.

The South West African People's Organization and its leader, President Sam Nujoma, are expected to easily win another five years in office. Nujoma, 70, led the 23-year struggle for liberation from South Africa and has ruled Namibia since its independence in 1989.

Seven other parties competed in the poll. But only the Democratic Turnhalle Alliance, which holds 20 percent of Parliament's seats, and the Congress of Democrats, a new party formed by disgruntled SWAPO members, were expected to make an impact.