Less than three weeks before an elaborate National Day of Honour ceremony takes place on Parliament Hill, several top soldiers who played key roles in the Afghan mission have yet to be invited, CTV News has learned.

The Day of Honour will commemorate Canadian troops’ service and sacrifices in Afghanistan. But former chief of the defence staff Rick Hillier, who shaped the military mission in Kandahar, said he has seen “none of the details or invites.”

Retired lieutenant-general Andrew Leslie, who is seeking the Liberal nomination in the Ottawa-Orleans riding, says he’s received “no formal invitation” to the May 9 event.

Retired colonel Pat Stogran, the outspoken ex-veterans ombudsman, also says he hasn’t received an invitation.

All three men have been critical of the Harper government and critics say the fact they haven’t yet been invited shows that the National Day of Honour is a “purely partisan event.”

“And because it is a partisan event, it will be diminished greatly,” said Liberal MP John McKay.

Even retired general Walt Natynczyk, the former chief of the defence staff who now heads up the Canadian Space Agency, said through his staff that "his schedule has yet to be confirmed."

Government websites promoting the National Day of Honour give little information about the event. Prime Minister Stephen Harper wrote to all MPs, urging them to "to mark the day by attending events staged at local legions."

But some legions say they haven’t received any direction from Ottawa.

“What are we supposed to do?” asked Scott Ferris, director of marketing at the Royal Canadian Legion. “What time of day? We understand there's supposed to be 2 minutes of silence -- when does that take place?”

Veterans are now questioning the lack of planning for the event that has been three years in the making.

“We sort of feel like we're scrambling, and it's tough to try to put together something that's really going to do honour to these people properly,” said Ferris.

Defence Minister Rob Nicholson told CTV News Wednesday that planning is well underway and more details will be shared next week.

With a report from CTV’s Richard Madan