HONG KONG (Reuters) - Hong Kong will re-launch its inaugural retail green bond this month as the coronavirus pandemic eases to raise as much as HK$20 billion ($2.55 billion), the city's financial chief said on Sunday.

The Asian financial hub last month delayed a sale worth HK$6 billion because of the rapid spread of COVID-19.

The three-year green bond issue, which includes a quota from the new financial year that started in April, will be worth HK$15 billion, and it can be increased to up to HK$20 billion upon over-subscription, Financial Secretary Paul Chan said in a blog post.

The bond will have a rate of 2.5%, up from 2% for the planned sale in March, he added, and will be open for subscription by the end of this month.

Hong Kong has stepped up efforts in recent years to become a leader in environmental and social governance, including the creation of working groups with government officials and global firms to develop a talent pool.

But its ambition to become a hub for green and sustainable business has been under threat from its tough border controls against COVID, which make it harder for financial institutions to attract specialist staff.

($1 = 7.8387 Hong Kong dollars)

(Reporting by Clare Jim; Editing by Robert Birsel)