Treasurer Andrew Barr said the spending would have minimal impact on the bottom line, with the budget already heading for a $361 million deficit this year.

The biggest item of the extra spending is $15.7 million for a public servants' pay rise. They will get an immediate $2100 boost (or 2 per cent, whichever is greater), another 1.5 per cent from July, and 1.5 per cent every six months from April next year to April 2017.

The budget changes announced yesterday also correct a half-million-dollar ''numerical error'' in the 2013-14 budget. A spokesman for Mr Barr said a loan for works at Exhibition Park had been wrongly set at $1.05 million instead of $1.5 million, so the error was corrected yesterday.

The spending includes $520,000 on design work for the big-picture City-to-Lake transformation of the lake's west basin, and $3.6 million for the courts - $1.1 million for judges' pension and retirement pay, $1.2 million for work on an extension of the prison, and $1.3 million for renovations to the court buildings.

The government also allocated an extra $7.6 million to its concession program, which helps Canberrans struggling to pay household bills, including electricity and gas, water and sewerage, rates, public transport, car registration, glasses and driver's licences. Mr Barr said the money was needed to cover extra demand, including the ''services-access card'' for asylum seekers, an expanded life-support rebate and the ageing population. Up to 24,000 Canberrans access the help each year.

The asylum seekers card gives holders subsidised transport, education, legal services and healthcare, and although introduced in 2011, it is only just starting to be understood, Mr Barr said. The life support rebate helps about 600 Canberrans a year to use medical heating or cooling equipment in their homes.