The Scottish Government is striking the right balance between investing in roads and greener forms of transport, the transport minister said.
Keith Brown spoke out after a report accused ministers of having a "perverse set of priorities" when it came to spending in this area.
Transform Scotland, which campaigns for more sustainable transport, accused the SNP administration of accelerating work to dual the A9 road from Perth to Inverness at the same time as "savagely cutting" plans to electrify the rail network in central Scotland.
Its report said: "It is clear that the path towards a sustainable transport system in Scotland remains long and challenging. Most damagingly, the Scottish Government's own investment agenda has decisively moved to subsidising increased road use and away from investing in sustainable transport.
"Its announcements over summer 2012 - an acceleration of plans for dualling of the A9 while savagely cutting back the scope of rail electrification in the Central Belt - demonstrate a perverse set of priorities, suited neither to tackle the environmental crisis nor the need for development of sustainable economic growth."
Transform Scotland argued investing more money in sustainable transport - such as public transport, walking and cycling - would help the Government meet climate change commitments and generate an "array of wider economic, social and environmental benefits".
However the minister said the Scottish Government was investing about £1 billion in public transport this year alone.
Speaking on BBC Radio Scotland's Good Morning Scotland programme, Mr Brown said: "We believe we are finding the right balance between contributing to public transport initiatives across the country, but at the same time we have to repair and we have to maintain the roads we have. Obviously not least because buses, cyclists and even future tram users have to use road and we have to have our roads in a good condition."
Mr Brown said he would "much rather have seen investment carried out by previous governments" to improve the A9. He also said improvements to the rail network should also have been tackled by earlier administrations.
Mr Brown said a "huge investment" of about £650 million is going into improving the main railway between Edinburgh and Glasgow, pledging: "We will carry out further phases of that project." He said there "should really have been much more progress by previous governments, but we are doing that".