At least 42 Members of Parliament (MPs) have failed to declare their interests by the set deadline and are in breach of members' code of ethics.

However, the chairpersons of the Joint Ethics Committee does not want to name them just yet.

At a press briefing on Tuesday, chairpersons Amos Masondo and Aumsen Singh announced that all MPs who were legally obliged to disclose their interests for 2017 have done so.

"However, the committee is concerned by the growing number of late disclosures and has resolved that these cases be investigated," Masondo said.

Singh said 42 members failed to meet the September 30, 2017 deadline.

The committee resolved that their conducted amounted to a breach of the code of ethics and that implicated members would have to explain.

The committee will then decide on the appropriate steps that should be taken.

"We'd rather not talk about names now," said Masondo, after they were asked to name the MPs.

"There is a process in place. All members will be given an opportunity to explain why they submitted late," he said.

"We are not punitive in our approach. We seek to ensure we correct the behaviour of members."

Singh listed the steps the committee could recommend: a reprimand in the House; a fine not exceeding 30 days' salary; a deduction in pay not exceeding 30 days; or the suspension of certain activities reserved for MPs.

Should a stiffer sanction be necessary, the whole of the National Assembly or National Council of Provinces may make such a recommendation, said Masondo.

Meanwhile, the committee has been granted permission to meet during the upcoming, extended constituency period to deal with outstanding cases.

Masondo said the committee considered 36 cases, of which 16 were finalised, 10 were ready for consideration, eight were under investigation and two were awaiting finalisation.

Last week, Masondo said the committee took on the cases of two African National Congress MPs, former deputy minister of higher education and training Mduduzi Manana and former state security minister Bongani Bongo.

Manana is facing two separate charges of misconduct - one for an incident that led to his conviction for assault and another relating to the alleged abuse of his domestic worker.

Bongo was accused in November last year of attempting to bribe the Eskom inquiry's lead evidence adviser, advocate Ntuthuzelo Vanara.