Abuja — Nigeria’s president signed a record 9.12-trillion naira ($29bn) budget for 2018 into law on Wednesday but said he would use a supplementary spending plan to seek changes, creating uncertainty about the final details of his growth strategy.

Muhammadu Buhari is pushing to foster growth in Nigeria, which has West Africa’s biggest economy, before an election next February in which he will seek a second term.

Nigeria’s parliament, the National Assembly, passed the budget last month.

The total sum is higher than the 8.6-trillion naira spending plan presented to parliament by Buhari in November, which legislators said was due to an increase in the assumed oil price to $51 per barrel from $45.

Buhari was critical of changes made by the National Assembly, which he said cut a total of 347-billion naira for 4,700 projects submitted to it for consideration.

In addition, legislators introduced 6,403 projects of their own amounting to 578-billion naira. He cited examples of funds being cut, including 8.7-billion taken from a housing programme, and said legislators added projects that were not properly assessed. Buhari also said parliament increased its own budget from 125-billion naira to 139.5-billion naira.

"I have decided to sign the 2018 budget in order not to further slow down the pace of recovery of our economy," said Buhari in a speech after the signing. "It is my intention to seek to remedy some of the most critical of these issues through a supplementary and/ or amendment budget, which I hope the National Assembly will be able to expeditiously consider," Buhari said.