Formern President Jacob Zuma spent R15.3 milion on legal fees during his nine-year so-called "spy tapes" challenge, according to a letter by the state attorney on Tuesday.

DA leader Mmusi Maimane on Wednesday confirmed that he had received a letter from the state attorney's office in Cape Town that confirmed the amount.

The DA approached the Western Cape High Court in November to compel Zuma to reveal how much he had spent on the case as president, after he failed to answer the question in Parliament.

The state attorney said the office was instructed by new President Cyril Ramaphosa to provide the details after having considered the court approach.

"We are instructed to inform you that since May 1, 2009 an amount of R15 300 250 was incurred by the Presidency on legal costs pertaining to the National Prosecuting Authority's decision to decline to prosecute former president Zuma on charges of fraud, corruption and racketeering."

Ramaphosa will convey the information to the National Assembly in due course, the letter said.

Economic Freedom Fighters leader Julius Malema is to ask Ramaphosa, during his first question session on Wednesday, how much Zuma spent on all legal costs during his nine years as president.

Zuma must pay back the money

Maimane said Zuma was now liable to pay back the money, because the spy tapes case was against him in his personal capacity, and before he was president.

"He [Zuma] was not a respondent in that case in his capacity as president of the Republic of South Africa.

"As such, this amounts to R15.3m of irregular spending by the government to keep Jacob Zuma out of jail.

"Therefore, Jacob Zuma must personally pay back this money. The DA has consulted our legal team and begun the legal process of retrieving every cent of this R15.3 million from Jacob Zuma."

Maimane also called on Ramaphosa to join their legal action to recover the money from Zuma.

"The new president cannot talk tough on corruption and wasteful spending, yet turn a blind eye to this blatant abuse of public funds by Jacob Zuma.

"We will retrieve the people's money from Jacob Zuma, and he will eventually have his day in court and will have to answer to the 783 counts of fraud, corruption, money-laundering and racketeering against him."

Malema's question also asked on what basis the State Attorney's office justified its spending on Zuma's cases.

Ramaphosa is due before the House at 15:00 on Wednesday to answer Malema's and five other questions during his maiden question session as president.