The Speaker of the National Assembly, Max Sisulu, has found DA MP David Maynier did not break any parliamentary rules by disclosing classified information on arms deals.

Sisulu qualified his decision however, by saying the case may have pointed to a gap in the rules, a point the Democratic Alliance on Monday said was "deeply problematic" as this could hint at a move to discourage MPs from asking tough questions.

The Speaker communicated his findings in a letter to Nyami Booi, the chairman of Parliament's portfolio committee on defence, dated September 24 - three weeks after the ANC urged Sisulu to expel Maynier from the committee.

"There is no basis for me to take action against the member," Sisulu stated.

He added however that the case had identified a possible gap in the rules governing MPs' conduct and said he would "refer the matter to the National Assembly Rules Committee to develop the necessary rules".

Sisulu also said that it did appear as though Maynier may have contravened the National Conventional Arms Control Act by making known information about pending weapons sales.

He said the matter should therefore be referred to the National Conventional Arms Control Committee (NCACC) to decide whether it wanted to lay charges with the police or the National Prosecuting Authority (NPA).

Maynier has led a campaign to force the NCACC to disclose details of what he calls "ten dodgy arms deals" with nations like Libya, Syria, Venezuela and Zimbabwe.

He also claimed a South African weapons company may have been guilty of "sanctions-busting" by trying to import aviator G-suits made in a third country and passing these on to Iran in violations of an arms embargo.

He has repeatedly refused to reveal his sources.

ANC members of the defence committee accused him of making public secret, stolen information and called for his removal.

The state law advisor and Parliament's law adviser were divided on the matter.

The latter said since Maynier initially revealed the information at a press conference and not in Parliament, he was not covered by parliamentary privilege and had broken the law.

But the state law advisor disagreed, saying it was unclear. He said an investigation was needed to determine whether Maynier had fallen foul of the rules of the legislature or the National Conventional Arms Control Act.

The DA said on Monday said Sisulu was misguided in referring the matter to the NCACC.

"The Speaker... is acting to blur the separation of power that should exist between the executive and the legislature. If the NCACC wants to pursue charges, that option was open to it from day one, it does not need a recommendation from the legislature to do so."

DA chief whip Ian Davidson said if the NCACC were to act now "the impression would be created that the law prevented the Speaker from acting and he has simply outsourced this issue to the executive, in the form of the NCACC, which is a Cabinet committee."

He added that it appeared Sisulu wanted to write new parliamentary rules that would "criminalise" attempts by MPs to hold the executive to account "by asking hard questions".

Davidson said he would take the matter up with Sisulu.