Two more groups of soldiers have left Canada for a six-month tour of duty in Afghanistan as part of a troop rotation that will see their counterparts in the country's war zone return home over the next two months.

About 40 members of the First Canadian Field Hospital were given their final briefing on Friday at Canadian Forces Base Petawawa in Ontario before shipping out, while around 130 reservists and military personnel flew out of CFB Gagetown in New Brunswick.

In a drill hall at CFB Petawawa, Col. Dennis Thompson offered warm wishes, but also a warning to soldiers bound for Afghanistan.

"In 2006, Canada lost one diplomat and 36 soldiers, 15 of whom were from this base."

A total of 44 Canadian soldiers have been killed in Afghanistan since 2002.

Hundreds of other soldiers from Petawawa will be deploying to Afghanistan over the next few weeks.

Chief of Defence Staff Rick Hillier recently said the soldiers should anticipate a spring offensive from the Taliban.

At Friday's departure ceremony, the medics said they're aware of the dangers they'll face.

Warrant Officer John McDonald, who'll serve in an artillery unit, said they're ready. "Drop the puck. It's time to go. We've been here. I want to get going."

McDonald has never been to Afghanistan. Neither has Master Bombardier Christian Jax, who said he has been told the majority of Afghans want the Canadians' help.

"There's of course a small percentage who don't want us there. And so we're going to have a little bit of turbulence," he said.

About half of the new wave of 2,500 soldiers heading to Afghanistan comprise military men and women belonging to units from Atlantic Canada.

Others will come from the 3rd Battalion, Princess Patricia's Canadian Light Infantry based in Edmonton.