International airfares are expected to increase from Sept 15 with the reinstatement of a fare-regulating scheme suspended after last year's terror attacks in the United States, an official said Monday.

The Market Development Programme (MDP) will be reinstated with new conditions and a new price structure, a spokesman for the Malaysian Association of Tour and Travel Agents (Matta) told AFP .

"The details, like what percentage of a price increase will be imposed, I can't confirm yet," he told AFP after a meeting between the MDP working group and Matta.

"But all the airlines must adhere to the scheme, and there are strict penalties for violations," he said.