Fed budget in March year surplus: CommSec

Australia's budget is in the black for the first time in a decade, with a surplus of $1.54 billion for the 12 months to March, according to CommSec which has drawn on its own full-year calculations.

CommSec proclaimed the underlying cash surplus after the release of the federal government's latest monthly financial statements on Tuesday.

The Department of Finance figures showed that in the nine months to March, the underlying cash budget balance was a deficit of $8.1 billion.

But by using available government financial data for a full 12 months, CommSec calculated there was actually a March year surplus of $1.544 billion.

"The last time the budget was in surplus was in the year to January 2009," CommSec said in a client note.

"The turnaround in the budget position is nothing short of remarkable ... The hard part now is to keep the accounts balanced or in small surplus."

The timeframe for the federal budget position is officially based on the traditional financial year, which runs from July 1 to June 30.

The coalition government is currently forecasting a deficit of $4.3 billion for the 2018/19 year and a surplus for 2019/20.

The actual 2018/19 result won't be known until the full year financial statements are released by the department in September.

And while CommSec's surplus number is unlikely to be in play when September comes around, the department's own nine-month numbers still reflect a significant turnaround in the budget position.

It has improved by $4.6 billion on the 2018/19 deficit forecast in the mid-year budget update, released in December.

The government raked in $544 million more revenue than expected in the period and spent $4.165 billion less.

The coalition has vowed to deliver a surplus of $7.1 billion at the end of 2019/20 if it's re-elected in May.

"Our budget shows that Australia is back in the black and back on track, with the first surplus in more than a decade," Treasurer Josh Frydenberg told reporters in Melbourne on Wednesday.