United Nations (United States) (AFP) - Governments that crack down on migrants are only harming themselves, UN Secretary-General Antonio Guterres warned Thursday ahead of UN talks on a global response to migration boycotted by the United States.

Guterres presented a report to the General Assembly on ways to address the plight of the 258 million international migrants, some of whom are trapped in legal limbo.

"Authorities that erect major obstacles to migration - or place severe restrictions on migrants' work opportunities - inflict needless economic self-harm," Guterres said.

"They impose barriers to having their labor needs met in an orderly, legal fashion."

"Worse still, they unintentionally encourage illegal migration," he said.

President Donald Trump's administration is threatening to deport thousands of immigrants who came to the United States illegally as children and were allowed to stay under the Deferred Action for Childhood Arrivals (DACA) program, which Trump has since scrapped.

UN member-states will next month open negotiations on a global compact for migration that would encourage governments to offer more legal venues for migrants, but the United States will not be at the table.

US Ambassador Nikki Haley cited concerns over sovereignty, saying "our decisions on immigration policies must always be made by Americans and Americans alone", even though the document is non-binding.

Calls for stronger cooperation to address migration followed the 2015 refugee and migrant crisis in Europe, when countries were overwhelmed by the flow from Syria and Libya.

The total number of international migrants has grown by 49 percent since 2000 and now represents 3.4 percent of the world's population, according to the United Nations.

The majority of migrants move across borders legally, but Guterres warned in his report that climate change and demographic trends will lead to a further spike in migration in the future.

Describing migration as a "positive global phenomenon," Guterres called for greater international cooperation to protect vulnerable migrants.

The global compact will be adopted in December at a conference in Morocco.