The party said it will include a commitment on the issue in its manifesto for next year’s Holyrood election.
The Scottish Campaign for National Parks and the Association for the Protection of Rural Scotland have been campaigning for an extension to the two current parks.
They want places such as Glen Affric, Galloway and the area around Ben Nevis and Glencoe to join Loch Lomond and the Trossachs and the Cairngorms national parks.
The designation of further parks would have a positive effect on local economies and help to protect landscapes and habitats, campaigners say.
Conservative tourism spokesman Murdo Fraser said ministers had failed to make progress on the issue despite a pledge in the party’s 2011 manifesto to “work with communities to explore the creation of new national parks”.
He said the estimated cost of £7 million to set up a national park would be outweighed by the economic and environmental benefits.
Mr Fraser said: “It’s clear the creation of Scotland’s two national parks has been a great success, and now is the time to extend that.
“All over the world national parks have a huge significance for tourism and the environment, and considering Scotland’s reputation as an outdoors destination it would be foolish not to capitalise on that. It would provide great economic benefits for the areas involved, and help protect some of Europe’s great wilderness areas.
“Designating certain areas as national parks would not only allow local people to become more involved with the landscape on their doorstep, but it would help conserve it for future generations too.”
A Scottish Government spokeswoman said: “While ministers remain committed to working with communities to explore the creation of new national parks, the Scottish Government has been equally clear that this would only be appropriate where there was strong support from communities and evidence to justify the case.”