President Robert Mugabe's government on Wednesday ordered a probe into charges that Zimbabwe's main opposition party received funds from foreign governments illegally.
But Nigeria and Ghana denied they gave funds to the Movement for Democratic Change (MDC) and said their only involvement with the opposition had been in trying to mediate in the country.
Zimbabwe's Justice Minister Patrick Chinamasa was quoted as saying he would ask police to investigate a possible breach by the MDC of the Political Parties Finance Act.
The act forbids foreign funding and the alleged breach followed accusations by an MDC MP that his party had recently received money from Ghana, Nigeria and Taiwan.
"I will draw to the attention of the Commissioner of Police ... the revelations made by the Honourable Job Sikhala," Chinamasa said in quotes to the state Herald newspaper on Wednesday. "They will advise us accordingly."
The penalty for breaching the act is a Zimbabwe dollar fine equivalent to the market value of the illegal foreign donation.
Sikhala, an MDC legislator, was quoted by local media on Monday as saying party leaders were squabbling over $2.5 million in funds received from Nigeria, Ghana and Taiwan.
He later withdrew the charges and in remarks broadcast on state television on Wednesday said he had made them in anger over the rifts bedevilling his party.
The MDC is split over whether to participate in November 26's election for the new 66-seat upper house of parliament.
MDC party leader Morgan Tsvangirai has ordered supporters not to stand in the poll, to avoid lending legitimacy to a government he says routinely rigs votes.
Tsvangirai's position has been opposed by his five top lieutenants, who argue the MDC has a national duty not to concede further political ground to President Robert Mugabe's ruling ZANU-PF party without a fight.
Some members have already registered to contest the polls.
MDC spokesman Paul Themba-Nyathi denied on Wednesday that the party had received money from the countries named.