Jetstar says any starter fare allows 7kg of combined carry-on weight between two items, at no additional cost.
The airline said customers who buy the more expensive FlexiBiz fare can already take up to 10kg on board with them as part of the bundle's benefits.
The move is another way of raising extra revenue, increasingly important for airlines whose base fares are at low levels due to competition.
Like Jetstar Air New Zealand allows 7kg in free carry-on but earlier this year put up check-in bag charges by up to 50 per cent for extras on its domestic jet flights. Air New Zealand also raised prices for excess bags by as much as 50 per cent this year.
Airlines around the world are making billions of dollars out of ancillary revenue with bag charges yielding an estimated US$23.6b ($32.4b) in the past year.
In the United States $US30 (NZ$45) bag fee is gaining traction as carriers seek to boost revenue to offset higher fuel prices.
United increased the charge for passengers' first checked bag by $5 last Friday, matching a move by JetBlue Airways earlier in the week.