The DA on Wednesday joined calls for the resignation of Armscor CEO Sipho Thomo, saying if he refused to do so, the board should fire him.

"Should Sipho Thomo not take the opportunity to resign, then Popo Molefe the chairperson of the Armscor board, must take action to terminate his contract," the Democratic Alliance's David Maynier said in a statement.

The state arms procurement utility board asked Thomo to quit last week, giving him three days, but he is yet to respond to the request.

Media reports quoted him as saying he had no reason to resign. Some MPs suggested that his handling of information about the cost of the now cancelled deal to buy Airbus A400M heavy-lift planes finally prompted the board to act.

Thomo admitted to shocked MPs last month that the cost had rocketed from an already steep R17-billion in 2006 to an "estimated" R47-billion.

Cabinet scrapped the deal last week.

The DA said Thomo's tenure as head of the acquisition agency was a "disaster" and had caused a protracted "civil war" within Armscor.

"Thomo was required to undergo counselling for his management style as well as a disciplinary hearing in relation to a sexual harassment case which cost the taxpayer more than R1.8-million," said Maynier.