A government study group on measures to reduce exhaust emissions from diesel-powered vehicles has compiled a midterm draft proposal calling for the replacement of older vehicles with new models, group sources said Tuesday.

The group -- made up of experts from the Transport Ministry, the International Trade and Industry Ministry and the Environment Agency -- proposed requiring owners of diesel vehicles manufactured in 1989 and before, when there were no emissions regulations, to replace their vehicles with new models, the sources said.

The study group had considered whether to require owners of all diesel-powered vehicles, regardless of when they were manufactured, to either install better mufflers with diesel particulate filters or to purchase new models, but decided an across-the-board application of that kind is not possible.