Some of the countries most affected by climate change should be an "inspiration" to rich nations on how to reduce their emissions, UN Secretary General Ban Ki-moon said on Monday.

Speaking at the Climate Vulnerable forum -- which brings together countries most affected by climate change -- Ban praised low-lying nations such as the Maldives, Costa Rica and Samoa for committing to be carbon neutral.

"In this time of global economic uncertainty, let (these countries') commitment to green growth be an inspiration to more developed countries -- the major emitters," he said.

He said it was unfair, however, to "ask the poorest and most vulnerable to bear the brunt of the impact of climate change alone" and called for the release of agreed funds for poor countries to adapt to global warming.

The meeting in Dhaka is for 18 countries most affected by climate change to agree a united front ahead of UN talks in Durban, South Africa in December where a "Green Climate Fund" will be negotiated.

The forum is a response to the fact that the pace of international climate negotiations is "very slow and inadequate" said Bangladeshi Prime Minister Sheikh Hasina, speaking at the opening on Monday.

Ban also praised low-lying and deeply impoverished Bangladesh for becoming a "world leader in disaster preparedness."

Using early warning systems and community volunteers, Bangladesh has significantly reduced the number of people who die during cyclones, showing the world that "natural hazards need not cause human catastrophe," Ban said.

Bangladesh is building more cyclone shelters, extending its climate resistance agricultural scheme, planting greenery along coastal belts to fight climate change -- all using its money from its domestic climate fund, Hasina said.

"We are bearing the brunt of the damage though we made negligible or no contribution to the menace. This constitutes a serious injustice... and demands immediate rectification and remedy," she said.