Cape Town - President Thabo Mbeki must not place the concerns of arms deal contractors before the interests of South Africans and the country's Parliament, the Democratic Alliance said on Monday.

DA public accounts spokeswoman Raenette Taljaard said in a statement it was in the public interest to have an open and transparent investigation into all allegations of corruption surrounding the country's controversial R43 billion arms deal.

"While everyone desires that the investigation be conducted expeditiously, any whiff of a cover-up or political pressure will be far more damaging than any 'open-ended' investigation."

She was reacting to concerns expressed by President Thabo Mbeki against an "open-ended" arms deal investigation.

Mbeki said during a live televised interview on Sunday that there were only allegations, and no prima facie evidence, of any wrongdoing in the deal.

He also warned that the "open-ended" investigation into the allegations was creating a negative message among the deal's major international contractors.

Taljaard said Parliament's processes must not be short-circuited to suit the main contractors in the deal.

"The president must not place the interests and concerns of the defence acquisition contractors before the interests and concerns of the South African voters, South Africa's Parliament and its key committees."

"Even if there were no allegations of wrongdoing, Parliament still would have a public duty to express a view on the expenditure priorities and the manner in which the spending priorities will be impacted upon by the arms acquisition," she said.

Parliament's watchdog public accounts committee (Scopa) will on Wednesday meet to debate its response to a letter from Deputy President Jacob Zuma, in which he criticised the committee for functioning outside of it powers.

Scopa has recommended a multi-agency probe into allegations of corruption linked to the arms deal. 

With acknowledgement to Sapa and News24.