The lawyer representing Britney Spears' ex-husband Kevin Federline has played down legal documents that have led to criticism of his client's lavish spending.

In recent court papers, submitted as part of the former couple's ongoing custody battle, Spears' attorney Stacy Phillips accused Federline of claiming business expenses, including "extraordinarily high tips for food and beverage services".

But Federline's lawyer Mark Vincent Kaplan insists such examples of extravagant spending are unrepresentative of the amounts the aspiring rapper usually tips.

Kaplan says, "He's totally getting a bad rap here. It seems like an unnecessary attempt to knock him when there's really no basis to do that."

Spears was recently ordered to pay Federline's legal bills, which Phillips says are excessive and which Federline can afford to pay himself.

But Kaplan counters, "Don't focus on whether he spent too much money going on a vacation or going to a restaurant. Focus - as the court does - on was he reasonable having to incur these fees? The answer is a resounding yes."

Spears and Federline are currently battling over custody of their two sons, Sean Preston, two, and Jayden James, one. Federline has full custody of the kids.