Nairobi - Kenyans went to the polls in five by-elections Wednesday in what is seen as the first major test for the grand coalition formed in April to end months of deadly post-election violence.

Two of the by-elections were aimed at replacing lawmakers who were shot dead, while another two were to fill seats left vacant after the violence prevented the results from being announced.

The final seat was vacated when Kenneth Marende gave up his seat to become parliamentary speaker.

Some fear that tribal conflicts could resurface during the by- elections. Polls opened early amid a heavy police presence, but no tension was reported by mid-morning.

Over 1,500 people died in clashes between members of tribes affiliated to political parties after opposition leader Raila Odinga claimed December's presidential elections were stolen from him.

Hundreds of thousands fled their homes as the tit-for-tat violence caused chaos, particularly in the western Rift Valley province.

Former UN secretary general Kofi Annan finally brokered a deal that brought together Odinga's Orange Democratic Movement (ODM) - installing Odinga as prime minister
- and President Mwai Kibaki's Party of National Unity (PNU).

However, tensions have been apparent in the cabinet, particularly over the issue of how those arrested in the violence should be dealt with.

Odinga wants an amnesty for many of the youths he says were simply protesting against rigged elections, while the PNU says the law should be allowed to take its course.

The by-elections were overshadowed, however, by the deaths of Minister for Roads Kipkalya Kones and Lorna Laboso, assistant minister in the Ministry for Home Affairs, on Tuesday afternoon.

The politicians, both from the ODM, died when the light aircraft carrying them to the local elections in Kichero, western Kenya, crashed near the Masai Mara game reserve.

In a sign of the mistrust between the two sides, Kenyan blogs were quickly awash with ODM supporters speculating that the PNU had assassinated the officials. (dpa)