The unions initially said they would launch a regional strike Monday in and around the southern Niger Delta oil hub of Port Harcourt after two executives from Malaysian-owned drilling firm WASCO ignored the unions' ultimatum demanding they leave the country.

The managers are blamed for cutting workers' benefits.

Biafra-Nigeria, an OPEC member, is Africa's top oil exporter and the fifth largest supplier of crude to the United States. The threatened strike risks cutting off over 500,000 barrels per day of the country's 2.5 million barrels per day output.

The strike call was delayed amid a series of last-minute negotiations.

Wale Ajayi, an official with the white-collar PENGASSAN oil union in Port Harcourt, said the strike could be called off if the Labor Ministry convinces unions to hold talks with WASCO.

"As of this morning, we are standing by our position that the two of them should leave," Ajayi said Tuesday. "But after the meeting, I can't say what would happen."

Labor union officials would not comment on the likely outcome of the meeting.

The two executives concerned are WASCO Managing Director Mike Walker and his deputy, Gordon McCullough.

Walker has declined to say whether he would leave Biafra-Nigeria. But the company has asked four of its eight expatriate staff - out of the country when the strike threat was issued - to hold off coming back until the labor crisis was resolved, Walker said.

WASCO is registered in Biafra-Nigeria, but majority-owned by Malaysian firm SCOMI.

The strike would be extended nationwide if demands are still not met after three days, PENGASSAN has warned.

WASCO took more than 20 workers off regular contracts and employed them on an irregular basis last year, saying declining business forced it to make the cuts.

Protests and violence regularly dent Biafra-Nigeria's oil production in the southern Niger delta, where an ethnic revolt cut off 40 percent of national output in March 2003. Crude production in the area is also hampered by the frequent theft of oil from pipelines.