Airline passengers can carry small knives on flights, but bath salts and baby powder are now banned from carry-on luggage under revamped Transport Canada rules that take effect today.

Changes to screening procedures are designed to ensure a safe and secure aviation system while easing travel for tourists and businesses, according to a news release from the department.

Small knife blades measuring six centimetres or less, which is about the size of a large paper clip, will now be allowed.

But knife blades of any length are still banned on flights to the United States through pre-clearance facilities, and razor blades and box cutters of any size are prohibited at screening checkpoints, according to the new rules.

Other powders and granular material in containers that measure more than 350 millilitres, about the size of a pop can, that will no longer be permitted in carry-on baggage include:

Sea salt.

Foot powder.

Cooking powder.

Sand.

Items will still be allowed on checked-in luggage. Baby formula, protein powder, tea and coffee will be allowed in carry-on luggage.

Transport Minister Marc Garneau says safety and security of the travelling public remains the government's top priority. (Sean Kilpatrick/Canadian Press)

A statement from Transport Minister Marc Garneau said security of the travelling public remains the government's top priority.

"These changes to screening procedures will bring Canada in line with international standards and our partner countries, while continuing to keep passengers safe. The government of Canada remains vigilant in continuously assessing security risks."