South Africa's competition regulator will announce its decision on Wal-Mart's $2,4-billion offer for local retailer Massmart at 12:00 GMT on Tuesday, a spokeswoman said.

Nandi Mokoena, a spokeswoman for the Pretoria-based Competition Tribunal, said in an e-mailed statement the decision would be released together with a statement from the Tribunal at 14:00 local time.

The reasons for the decision will be released within 20 working days after, she said.

Wal-Mart's bid to take a 51% stake in the South African discount retailer is seen as a test case for major foreign investment in South Africa.

Three government departments and the country's powerful unions have lined up against the deal, asking regulators to impose targets on local procurement and a freeze on job cuts.

The government and unions are concerned about Wal-Mart's global supply network which, they say, could lead to a flood of cheap imports, sparking job losses and squeeze local suppliers.

Wal-Mart, which already voluntered to preserve jobs for two years and spend R100-million to develop local suppliers, threatened to walk away or challenge the decision if local supplier targets are attached as conditions.