The United Nations Development Programme says criticisms in a report by its board are not relevant to former New Zealand prime minister Helen Clark's time as head of the programme.
The UNDP has an annual budget of about $US5 billion and has been criticised by the board in a report evaluating its efforts to reduce poverty.
The report covers the decade ending in 2010 - meaning only one year of Miss Clark's time in the role was evaluated.
The report says it is unclear how effective the programme's projects have been. It says that could be because evaluations are limited, but also reflects a lack of focus on the poor.
It says the poor are often not direct beneficiaries of the programme's projects, which include border management and advising on trade promotion.
Magdy Martinez-Soliman, the programme's deputy director for development policy, says during the time the report covers it had to focus on various issues, including democratic governance, gender equality and climate change.
Mr Martinez-Soliman told Radio New Zealand's Checkpoint programme on Wednesday the board's report is not relevant to Helen Clark's work.
"Ninety percent of the time that is under study that has nothing to do with Miss Clark's decision and steer of the organisation.
"Her leadership has been almost permanently demanding that we are tougher on poverty, that our programmes become more effective, that we are more results oriented and that we report very seriously what we achieve."
Mr Martinez-Soliman says he accepts that the UNDP needs to focus more on poverty.
One of the programme's goals is to cut the rate of extreme poverty in half by 2015.
Between 2004 and 2011, the UN spent more than $US8.5 billion on poverty, about 26% of its total programme. But according to the World Bank, there are still nearly 1.3 billion people living in poverty, down from over 1.9 billion in 1981.
The report recommended that the UNDP forges stronger links with wider communities and more partnerships with other UN agencies, as well as more specific targeting of poor communities.
Michael Powles, a former New Zealand ambassador to the United Nations, believes there may be an ulterior motive to the criticisms, saying UN bureaucracy has camps and groups within it who conduct campaigns.
