Nigeria’s main labour unions have shut down the national electrical grid and disrupted flights across the country as they began an indefinite strike over the government’s failure to agree a new minimum wage.

The strike is the fourth embarked upon by the Nigerian Labour Congress (NLC) and the Trade Union Congress (TUC), two of the country’s biggest union federations, since President Bola Tinubu took office last year.

The Transmission Company of Nigeria (TCN) said on Monday that union members drove operators away at power control rooms and shut down at least six substations, eventually shutting down the national grid at 2:19am (01:19 GMT).

Nigerian airline Ibom Air said it was suspending flights until further notice due to the strike while another, United Nigeria, said airports across the country had been shut down and striking workers had permitted none of its flights to operate.

Electricity and aviation unions said in a statement they had directed members to withdraw their services in compliance with the indefinite strike.

“We demand a living wage,” the NLC said on X. It and the TUC represent hundreds of thousands of government workers across key sectors.

The unions want the current minimum monthly wage of 30,000 naira ($20) to be increased to nearly 500,000 naira ($336). The government has offered 60,000 naira ($40).

The unions’ demand would increase the government wage bill by 9.5 trillion naira ($6.3bn), which is capable of “destabilising the economy”, Information Minister Mohammed Idris said.

Since taking office, Tinubu has embarked on reforms that have fuelled inflation, sending it to an almost 30-year high, and worsened a cost-of-living crisis in Africa’s most populous nation.

He has been under pressure from unions to offer relief to households and small businesses after scrapping subsidies on petrol, which previously kept fuel cheap but cost the government $10bn a year.

Unions declared an indefinite strike on Friday after talks over a new minimum wage collapsed. They said the strike would last until a new minimum wage is in place.

The TCN said it was making an effort to recover and stabilise the national grid, but unions were obstructing grid recovery nationwide.

Unions have also demanded a reversal of an electricity tariff hike that went into effect last month for better-off consumers who use the most power as the government tries to wean the economy off subsidies.