Samson Siasia, Nigeria’s former under-23 coach, has given the Nigeria Football Federation (NFF) a two-week ultimatum to settle its debt to him.
Siasia says the NFF owes him five months’ salary arrears from the start of April to August 2016.
The 49-year-old led the country to a bronze medal finish at the Rio Olympics.
Barely five weeks after ending his two-year contract on a high, Siasia said his patience is fast running out.
“I have given them a two week ultimatum to pay me or I will sit inside the NFF office in Abuja until I get paid,” Siasia told BBC Sport.
“The national team is preparing for a World Cup qualifier and to be honest my unhealthy distractions are the last thing they need right now.
“I’ve made it clear in my letter that my assistants and I should be paid the backlog owed because it’s inhuman.
“As head of our families we sacrificed everything for the country but the NFF refused to pay us – it’s not only heartless but wicked,” he said.
A top NFF official acknowledged the debt but said Siasia’s latest remarks are “unfortunate”.
The NFF attributed the delay to the latest financial procedures which must be adhered to by all.
“There’s a new financial procedure in place, which has not been concluded by the federation,” the NFF official told BBC Sport.
“His latest outburst is just unfortunate but the process (to pay him) is still ongoing. There is no attempt to deny Siasia or his assistants their dues.”
As a player Siasia won the 1994 Nations Cup and played for Nigeria at their maiden appearance at the 1994 World Cup.
He was in charge when Nigeria finished as runners-up at the 2005 Fifa U-20 World Cup in the Netherlands.
He led the country to the 2015 African U-23 championship and also coached them to silver and bronze medals at the 2008 and 2016 Olympics football event.
It is not the first time Nigerian coaches have been caught in the web of unpaid salaries.
Recently the likes of Christian Chukwu, Shuaibu Amodu, Eucharia Uche, John Obuh, Austin Eguavoen, Stephen Keshi and Sunday Oliseh have gone to the media after seeking payment for outstanding salaries.