Jetstar has started charging passengers to travel with babies on their laps during domestic and international flights.

Passengers on the budget airline will pay $30 per one-way journey to carry a child up to two years old on their lap on domestic Australian flights and $50 on international flights.

The charges came into effect on Monday. It was previously free to bring infants on domestic flights and on flights between Australia and New Zealand. Other international flights previously had a $40 fee.

A Jetstar spokeswoman said introducing the charges brought Jetstar into line with its low-cost competitor Tigerair.