A Zambian immigration spokeswoman said the Movement for Democratic Change (MDC) delegation entered Zambia on Thursday on a tourist permit but checked into a hotel under false names, which was a breach of regulations.
She said it was routine to expel people in such circumstances.
Nelson Chamisa, a spokesman for the MDC, said that Tsvangirai followed all the relevant immigration laws to the letter and thought that the incident was politically motivated.
The MDC, which once posed the most serious challenge to the 25-year rule of Robert Mugabe, the Zimbabwean president, split into two after party officials defied Tsvangirai's call to boycott senate elections in November.
Tsvangirai said the elections were a waste of money at a time of serious food shortages, growing unemployment and galloping inflation.
Last week, Tsvangirai officially visited Zambia and met Levy Mwanawasa, the president, before holding various meetings opposition and civil society groups.