Authorities in the capital city need to do more to ensure Hanoi 's continued development is eco-friendly and "climate-proof", according to a UN climate change expert.

Speaking at a press conference held by the UN's Habitat organisation in Hanoi on April 13, UNDP Policy Advisor on Climate Change Koos Neefjes said that while existing master planning for Hanoi took into account certain climate factors, "it is not entirely clear how Hanoi plans to adapt to climate change effects, particularly with regard to water supply or with regard to flood safety."

Koos said the city's plans lacked details and could do better on providing both a vision and practical measures on moving towards a low-carbon city.

He warned that the capital city's expansion into vulnerable or flood-prone areas should be minimised or completely eliminated as soon as possible, because "once (the city) expands to lower land, it is not going to be moved."

The press conference was held as part of a wider programme on highlighting climate change threats to cities around the world.

Also speaking at the event, Habitat Programme Manager Nguyen Quang said many new urban areas in Vietnam were expanding along the coast line, so city planners must carefully consider how to develop these areas in the safest way possible.

Planners should take into account threats from tsunamis and floods, not only at present, but also in years to come.

"It is also very important to mainstream disaster risk reduction into the urban development process," Quang said.

To do so, he suggested authorities focus on improving land-use planning and land-use suitability analysis methods.

In particular, city planners should re-orientate urban areas to higher ground to avoid climate-related risks.

As Vietnam has to accept limitations on funding and resources, experts said investment priorities should be taken very seriously.

For example, instead of spending too much money dealing with possible future problems, authorities should prioritise the most urgent existing problems facing urban areas.

Koos said the most important task was to improve protection mechanisms, especially flood protection mechanisms, including flood gates, bypass canals and dykes.

Especially urgent was the need to reinforce river and sea dykes in coastal areas.

"It is not about every dyke becoming a little bit higher, it's about certain dykes being improved," said Koos. According to a report recently released by the UN, by 2100, Vietnam will experience an increase in the average annual temperature of about 2.3 Celsius degrees compared to the last decades of the 20th century due to climate change, which will be felt especially in the northern parts of Vietnam, including Hanoi.

The northern regions will also face more frequent and extreme rainfall events and flooding.

One example of this trend is the unseasonable and extreme rainfall witnessed by Hanoi in November 2008.

The southern regions are also under threat, and should plan for more droughts due to higher temperatures and a decrease in annual rainfall.

Ho Chi Minh City , in particular, will face the threat of a rising sea level and salt water intrusion, according to the report.

During the 1990-2009 period, Vietnam ranked fifth among ten developing nations most affected by climate change effects. /.