Said Darwazeh, the Jordanian health minister, said on Friday at least three dead turkeys at a domestic farm in Ajloun had tested positive for the disease but none of the humans tested in the area were infected.
Twenty people were given the Tamiflu antiviral drug and the area has been cordoned off to prevent the disease from spreading further, he said in Amman.
"The disease in its current form is more of an economic disease that affects poultry. It has had a very limited effect on human health," he said.
The virus had already been detected in some of Jordan's neighbours and other countries in the region.
Iraq, Turkey and Egypt have reported human cases and infected poultry was found in southern Israel and spread to the densely populated Gaza Strip this week.
Darwazeh said Jordan had been on high alert since bird flu was detected in Israel and that its own outbreak was isolated.
The H5N1 bird flu virus reached Jordan after rippling out from Asia to the Middle East, Europe and Africa.
It can infect people who come into close contact with infected poultry.
The virus has killed 104 people since 2003 according to the World Health Organisation figures, updated on Friday.
Experts fear the virus will mutate into a form that passes easily from person to person, starting a pandemic in which millions could die and which could cripple the world economy.
Darwazeh told Reuters that Jordan had notified the WHO of the cases and would ask it for technical assistance if there was a serious outbreak.
"So far I think the situation is under control," he said.
The office of Tzipi Livni, the Israeli foreign minister, said Kofi Annan UN Secretary-General had agreed to reinforce UN aid teams to combat the virus' spread in the affected Palestinian areas after a plea for assistance.
Israel Radio reported that Israel and Jordan were co-ordinating efforts to combat the spread of the virus.
An outbreak of H5N1 in Israel prompted authorities to cull 1.2 million birds at 13 farms. Israel Radio quoted agriculture ministry officials as saying they had not detected any new cases of the virus in the country.
Jordan began culling birds within a 6km radius of the outbreak on Friday. Birds further away will be vaccinated.