Labor says it would consider forcing employers to turn casuals to permanent staff after six months, halving the amount of conversion time ordered by the Fair Work Commission earlier this year.

In comments that are set to further inflame tensions between Labor and business groups as they kick-start another year of battle over industrial relations, the Opposition's employment spokesman Brendan O'Connor accused some employers of being "their own worst enemy"

"They employ hundreds of casuals and then they wonder why the turnover in their workplace or their business is so high," he said on Wednesday.

"One of the reasons why turnover happens so quickly is because people cannot live indefinitely in work that's so precarious.