The National Treasury Management Agency has mandated dealers to issue a 12-year "green bond" in the near future with a market source saying the issue was expected to raise between €2 and 3 billion. 

The NTMA last week announced that it planned to issue its first ever bond in the increasingly popular category of green securities in the final three months of the year. 

"The syndicated transaction is expected to be launched and priced in the near future subject to market conditions," the agency said in a statement. 

When the NTMA has previously said it would issue debt "in the near future", it has sold the bond within 24-48 hours, a timescale the source confirmed was likely again this time. 

Although green bonds make up a small fraction of the overall bond market, global interest has soared as banks, sovereigns and companies look to tap the appetite for climate-friendly investments. 

Global green bond issuance hit a record $155.5 billion in 2017, surpassing previous estimates, and could reach $250-$300 billion this year, research from the Climate Bonds Initiative (CBI) showed in January.  

The NTMA has so far raised €13.5 billion of the €14-18 billion it plans to issue in long-term debt this year, and will also hold one more regular bond auction on November 8.