The resignation of Public Accounts watchdog chief Gavin Woods has dismayed opposition MPs, who are demanding that the next chair of the committee should come from their ranks.

Woods, a member of the Inkatha Freedom Party, said he was quitting over government interference in the inquiry by the Standing Committee on Public Accounts (Scopa) into the arms deal.

Raenette Taljaard of the Democratic Party described the move as "a tragic day for democratic accountability".

The United Democratic Movement said it regretted Woods's resignation, since he had done his job "with dedication and commitment, often in difficult times".

"Dr Woods brought to the position of chairperson a large array of skills and experience that enhanced the work of the committee," UDM finance spokesperson and deputy leader Gerhard Koornhof said.

The UDM called on all political parties represented in Scopa to ensure that it regained its mandate of integrity and independence.

"In the interest of parliamentary accountability and oversight, it is vital that an opposition MP should chair Scopa. Scopa must function independently from the executive."

MP Francois Beukman, New National Party media director, said Woods's resignation was unfortunate and that his contribution in promoting Scopa as a platform of parliament to ensure accountability from the executive should be recognised and respected.

"Events during the arms deal saga indicated that Scopa became so divided along party political lines that the overseeing and monitoring role of Scopa suffered a setback.

"Relations between the chairperson and some of the members became a constant source of conflict," Beukman said.

It was in the interest of the role of parliament that Scopa should be protected as a public watchdog to ensure accountability of public funds used by the executive, Beukman said.

"It is in the interest of parliament and multiparty democracy that the chairperson of Scopa should be a member of an opposition party.

"The chairperson should be allowed to play an independent and pro-active role."

He added: "Scopa should be in the service of the taxpaying public, and not be the primary arena to score party political points."

Taljaard said Woods' resignation "signals yet another blow to parliament's oversight role".

"Parliament has also lost its last fiercely independent chairperson from an opposition party," she said.

Taljaard said his resignation was the unavoidable and "probably ANC-desired outcome of the extreme pressure which the ANC's political control has placed on Scopa.

"The strong views of the ANC government on the arms probe have placed not only the probe itself under pressure, but also placed an insurmountable burden on the relationship between the ANC component of Scopa and its opposition chair.

"Dr Woods's resignation can hardly come as a surprise to the manipulative ANC that has set out through systematic and obstructive means in Scopa to sideline and eventually remove Andrew Feinstein and fundamentally undermine the chairperson of Scopa."