Public transport users in NSW face a 2.4 per cent increase in Opal fares from July, which the state government stresses is in line with inflation and needed to offset a decline in revenue.

The government has also kept the cost of all-day travel for seniors' Gold Opal cards capped at $2.50.

In attempting to head off what he described as Labor's "fare scare campaign", Transport Minister Andrew Constance said commuters could be guaranteed increases would mirror inflation while ensuring more public transport services were provided.

"We have adjusted the fares in line with inflation because we want to continue to put as much downward pressure on the cost of living [as possible]," he said.