The South African president, Jacob Zuma, should reimburse the state for 7.8m rand (£380,000) in a scandal over upgrades to his private home, according to a report by the national treasury.

The money amounts to a “reasonable percentage” of costs for improvements to Zuma’s Nkandla home that were unrelated to security, including a visitors’ centre, a swimming pool and a chicken run, said the report, which was delivered to the constitutional court on Monday.

The court had instructed the treasury to compile the report after ruling that Zuma violated the constitution by failing to comply with a government watchdog report that concluded he had inappropriately benefited from state funding.

The Democratic Alliance, an opposition party, welcomed the recommendation that the president repay a portion of the money spent on his home, but said Zuma should pay more. It noted that the 7.8m rand was just over 3% of the total amount, including security upgrades, that was spent on Nkandla.

Zuma has said he would be willing to reimburse the state. Some critics said his pledge had come too late and called for his resignation, although powerful factions in the ruling African National Congress have backed him.

On 3 August, South Africa holds local elections deemed to be a barometer of whether dissatisfaction over Zuma has eroded some support for the ruling party, which has been in power since the first all-race vote in 1994.