Chris Bowen will promise to name the date Labor will bring the budget back to balance by the end of the 2016 election campaign.

Mr Bowen's commitment will be made in Friday's lunchtime debate with Treasurer Scott Morrison at the National Press Club in Canberra.

The shadow treasurer will also say the opposition will not necessarily spend as much as the Coalition will promise to during the remaining five weeks of the election campaign. This may allow Labor to promise a stronger budget bottom line by the end of campaign, a move designed to head off the government's attack on the opposition over economic competence.