Zanu-PF wins by-elections delivered by Tsvangirai's MDC-T

President Robert Mugabe's party has won all 16 parliamentary by-elections held this week, state radio reported on Thursday.

"The ruling Zanu-PF romped to victory after sweeping all the 16 contested constituencies in yesterday's by-elections," the Zimbabwe Broadcasting Corporation radio reported.

Candidates from Zanu-PF won by huge margins in many constituencies, though turnout in some urban centres during voting on Wednesday was low, according to official voting tallies.

The Movement for Democratic Change (MDC) of Morgan Tsvangirai boycotted the polls. Zanu-PF already has an overwhelming majority in parliament.

In one of the most closely watched constituencies, Information Minister Jonathan Moyo won in the Tsholotsho North seat.

He said in a tweet that he wanted to thank Mugabe, Zimbabwe's two vice presidents and voters "for the landslide."

MDC-T leader Morgan Tsvangirai had urged his supporters to spoil their ballot papers.