Zimbabwe's opposition Movement for Democratic Change says it has expelled 26 members for defying its leader's boycott of the forthcoming election.
Mr Tsvangirai founded the MDC, which now faces division
Morgan Tsvangirai insists there is no point contesting the 26 November poll as the government will rig the vote and the new senate will have no real power.
But others disagree, and say they will continue to stand in the election.
The expulsion takes the party a step closer to a final split, says the BBC's Africa editor Martin Plaut.
The dissidents - which include several senior MDC members - may boycott the party convention in February, formalising the split, he adds.
Last week, Mr Tsvangirai called on members running in the election to "withdraw their candidature within seven days or it is acknowledged that they are not standing on the party ticket".
His spokesman William Bango said that deadline had now expired, and the members had "automatically expelled themselves from the party". He said the members would now run as independents.
But MDC Deputy Secretary General Gift Chimanikire - who supports the election - insists the 26 candidates are continuing with their campaigns.
"Those candidates are still going to stand as MDC candidates as accepted by the Zimbabwe Electoral Commission, which is a legal elections body in this country," he said.
Mr Chimanikire was one of several senior officials who refused to attend an MDC national council meeting in the capital Harare earlier this month to affirm Mr Tsvangirai's boycott of the election.
They described the meeting as illegal and accused Mr Tsvangirai - the trade union leader who founded the party six years ago - of unilaterally dictating party policy.
They argue that only by taking part in the election can they hope to increase the MDC's voice in the legislature.
These divisions come at a time when Zimbabwe's economy is in increasing difficulties.
Inflation is skyrocketing, there are constant power cuts in Harare, fuel is almost impossible to obtain and people are facing several food shortages.