An imminent rise in bus fares could see a drop in passengers, a public transport campaigner says.

The recession has been particularly savage on young workers with 18.4 per cent of the 15 to 24 age group now unemployed.

The Govt says its 25 cent increase to the minimum wage - about $10 a week - is all that can be afforded, but unions call it is miserly.

Lifting the minimum wage to $15 an hour would be "too significant a hike", the prime minister says.

Sixty-one per cent of people want the minimum wage lifted to $15 an hour, a Herald Summer Survey has found.