HARARE, MARCH 09 (Reuters) -- Zimbabwe's High Court on Tuesday refused to overturn the election of the first opposition Speaker of Parliament since independence, after a challenge by a lawmaker from President Robert Mugabe's ZANU-PF party.

The ruling will ease concerns within the MDC, which accuses its coalition partners in ZANU-PF of carrying out actions that seek to undermine the fragile unity government.

Lovemore Moyo, a senior official from Prime Minister Morgan Tsvangirai's Movement for Democratic Change (MDC) party, became the first opposition Speaker in August 2008 after the MDC ended ZANU-PF's majority in parliament in earlier elections.

But his election was immediately challenged by former information minister Jonathan Moyo -- elected on an independent ticket but rejoined ZANU-PF last year -- who argued that the vote failed to meet the test of a secret ballot.

Moyo said some MDC members had openly shown their ballot papers to other legislators in a move meant to influence them in their voting and that the whole process was chaotic.

High Court Judge Bharat Patel on Tuesday described the vote as "exuberant" and said while some MDC members had shown their ballot papers to colleagues, the actual voting was done in secret.

"It's clear that all members marked their ballot papers in secrecy and none were coerced to vote for any candidate," Patel said. "The application is therefore dismissed with costs."