HAMILTON -- The federal government has not slammed the refugee door shut on single men who might want to come to Canada as part of its large Syrian resettlement program, the bureaucrat in charge of the effort said Thursday.

Instead, the government has made its priority helping the most vulnerable Syrians and its primary aim is to help complete families make the move, Deborah Tunis said.

Tunis disputed reports that single men would be excluded, citing a technical briefing from David Manicom, the assistant deputy minister with Immigration, Refugees and Citizenship Canada.

Manicom, she said, directed that families, women, children and sexual minorities at risk take precedence.

"Those are where priorities are but we haven't said that we're not taking any single men, it's just that those other cases are going to the top of the list," Tunis told The Canadian Press in an interview.

"Single males will be coming as part of this population."

Tunis, a longtime employee with the federal government, came out of retirement to become the government's special co-ordinator on Syrian refugees.

It was an opportunity to participate in an important national project, make a contribution, and make a difference in people's lives, Tunis said.

"Our assistant deputy ministers this week said this is the most exciting, exhilarating thing they've worked on," she said.

"For many people in the department, they've been wanting to work on this kind of a project for a long, long time -- it's why people come to work."

Indeed, that kind of excitement was evident as Tunis and hundreds of other people devoted to helping refugees gathered for the start of a national three-day conference.

In the following days and weeks, the first wave of 10,000 Syrian refugees will begin arriving in Canada -- the government has said by the end of the year -- dominating discussions at the fall consultation of the Canadian Council for Refugees.

The logistics, however, of welcoming them is a daunting challenge -- even for organizations that have spent years helping refugees.

Jennifer Bond, an Ottawa professor now providing expert advice to the new refugee minister, said what's different is the change in attitude at the highest levels in the country.

"For the first time in more than a decade, we have a government committed to refugee protection," Bond said.

At the same time, she stressed, Ottawa needs significant support and co-ordination from other levels of government and local groups.

"This is truly an incredible mobilization," Bond said.

The Liberal government has also promised to resettle another 15,000 displaced Syrians by the end of February.

It's also not clear when money will begin flowing to the faith and other groups who will provide the on-the-ground support for the newcomers, but Tunis said it would likely be a matter of weeks.

Initially, housing will be a priority -- for example, some hotels and schools may offer immediate shelter -- but the list of tasks, from providing health care and language lessons to schooling and social supports, is long.

Aid organizations and others getting ready to help in those tasks can barely wait.

"No matter the timeline, they are coming," Loly Rico, the council's president, told conference delegates.

"We want to provide them with protection as soon as possible."

But even before the Syrians arrive, delegates were told of the mammoth crisis facing millions of others who are not receiving the same kind of global or Canadian attention.

Furio de Angelis, the representative of the UN High Commission for Refugees in Ottawa, told delegates that the gap between pledged aid to them and the need remains large.

"It's not sustainable," de Angelis said.