Billions missing for roads: Labor

The federal government says a $2.5 billion gap between what was flagged to be spent on roads and what actually went ahead is due to "rephasing".

Labor transport spokesman Anthony Albanese asked minister Darren Chester in parliament on Wednesday how $8 billion pledged in the 2014 budget to be spent in the 2015/16 financial year became $5.5 billion in actual spending.

"It is not unusual for major projects to be rephased into current years to meet the various deadlines," Mr Chester told parliament.