The Reserve Bank’s quarterly economic forecast has been used as campaign fodder by both Scott Morrison and Bill Shorten after some predictions matched those of the government but some undermined it.

On Friday the central bank said it was now forecasting year-average growth of 2.25% for 2018-19 and 2.5% for 2019-20. The figures for this financial year are down on those given by the RBA three months ago, but are “consistent” with the Coalition government’s federal budget forecasts, Scott Morrison said.

“We have always taken a conservative approach when it comes to our forecast,” he said.

However, those Coalition forecasts were not conservative enough to line up with the RBA’s predictions for 2019-20 – another drop on its last report and 0.25% below what the government had in the budget.

Furthermore, on a year-end basis, the central bank has slashed its forecast in the financial year to June 2019 to just 1.75%. That is down from 2.5% previously and a full percentage point below what is seen as Australia’s potential growth rate at 2.75%.

The disparity prompted the Labor leader, Bill Shorten, to quip that the RBA had “made the case indirectly for voting Labor”.

“Now is the time for strong economic management in the interests of working and middle-class people. Our set of books has caught the government flat-footed,” he said.

In its monetary statement on Friday, the RBA said the labour market was performing “reasonably well” and underlying inflation had been lower than expected. This was despite “subdued growth in household income and the adjustment in the housing market … affecting consumer spending and residential construction”.

“Non-labour sources of income have been subdued and are likely to remain so for a while, given the effects of the drought on farm incomes and of soft housing market conditions on the earnings of many other unincorporated businesses,” it reported.

“Strong growth in tax payments has also subtracted from disposable income growth over recent years.”

Having kept the interest rate unchanged since August 2016, the RBA said it would be paying “close attention” to the labour market in its coming meetings.

It is now considered relatively likely the central bank will cut the cash rate later in the year, having left them on hold for the 30th meeting in a row on Tuesday.

“There is really only one reason the Reserve Bank cuts rates and that is to stimulate economic growth,” Guardian Australia’s economics columnist, Greg Jericho, has written. “Unlike the government cutting tax cuts to curry favour and put money in the pocket of sectors of the electorate they wish to reward, the RBA does not need to get re-elected.”