* Outbreak has killed 180 in South Africa
* Neighbouring Namibia reports first case
* Inspectors barred from Tiger Brands factory (Adds officials denied access, gives Tiger Brands comment)
JOHANNESBURG, March 15 (Reuters) - The worst listeria outbreak on record is only in its early stages and will likely infect more people in South Africa and the region, health minister Aaron Motsoaledi said on Thursday.
The infection which can hit the blood system and brain has killed 180 people in South Africa since January last year. Neighbouring Namibia reported its first case on Tuesday and said the victim was fighting for his life in hospital.
"We are just at the beginning and we must expect other cases to emerge," Motsoaledi told reporters after meeting health ministers from across the region.
He said he was expecting more cases to be reported across southern Africa, without elaborating.
The government has linked the outbreak to "polony" - low-priced processed meats that are mostly consumed by the poor.
South African food producer Tiger Brands, which makes polony, said on Friday a department of health report had confirmed the presence of the LST6 listeria strain its factory in the northern city of Polokwane.
Authorities are also investigating a plant owned by RCL Foods that makes a similar sausage product, though they have not reported any discoveries of listeria.
Both companies, which say they are cooperating with the authorities, suspended processed meat production at their plants after health authorities ordered a recall of the products both at home and abroad.
Kenya, Zimbabwe and Zambia have banned imports of South African processed meat, dairy products, vegetables and fruit. Mozambique and Namibia halted imports of the processed meat items and Botswana said it was recalling them. Malawi stepped up screening of South African food imports.
Motsoaledi said he was concerned about an incident when health ministry inspectors had been barred from entering the factory operated by Tiger Brand's unit Enterprise Foods in Polokwane.
"We had to seek police to accompany them," Motsoaledi told Reuters after the meeting.
Tiger Brands said it had apologised for the incident but said the inspectors had not had a letter authorising entry.
"Since the health official had not been to the Polokwane facility prior, the security team said there were strict protocols for entry," said Tiger spokeswoman Nevashnee Naicker.
A human rights lawyer said over the weekend he would launch a class action lawsuit against Tiger on behalf of the families of people who died.
Tiger Brands Chief Executive Lawrence McDougal said last week that there was no direct link between the deaths and its processed cold meat products. (Writing by James Macharia Editing by Andrew Heavens)