The Economic Community of West African States (ECOWAS), West Africa's 15-member bloc, said on Sunday it would close borders and restrict the movement of cash and goods into Mali following plans by the country's military junta to delay elections by three years to 2025.

"The Authority finds the proposed calendar for a transition totally unacceptable. This calendar simply means that an illegitimate military transition Government will take the Malian people hostage during the next five years," ECOWAS said in a statement.

Mali's leadership, which seized control in a coup in May 2021, spoke out against the sanctions on Monday, calling them "illegal and illegitimate". It said it had decided to close its borders with ECOWAS member countries and recall its ambassadors.

But an inability to move supplies into Mali would make life tricky for miners, who are already suffering from spiralling costs in the wake of COVID.

Alexander Raymakers, senior Africa analyst at risk consultancy Verisk Maplecroft, said miners "should prepare for significant disruptions to their export routes and logistical supply lines as long as ECOWAS maintains its ban on trade and financial exchanges with the country".

"Considering the importance of the gold mining sector as a source of revenue for Bamako, we do not expect the bloc to provide any exemptions to miners," Raymakers added.

Publicly listed gold miners operating in the West African nation include Resolute, Firefinch and Hummingbird.

Analysts from Canaccord Genuity said the closing of borders and suspension of "non-essential" financial transactions "could have a material effect on Hummingbird's operations".

Hummingbird, which operates the Yanfolila mine in the south of the country, said it was "evaluating the immediate risks to our supply chain".

"Whilst all plans will be made to minimise the potential impact it is too early to say how these sanctions may potentially affect our business," added the AIM-listed producer.

Shares in Hummingbird were down by 6% at midday in London on Monday.

Resolute and Firefinch were unavailable for comment.

Shares in ASX-listed Firefinch fell just over 3.5% in Australia on Monday, while Resolute was down 3.57% in London by midday.