Ashlee Simpson. (AP File)

Singer/actress Ashlee Simpson-Wentz has slammed reports her marriage to Pete Wentz is in trouble amid rumours the couple is on the verge of a split.

The pop star is said to be struggling to balance being a mother to their seven-month-old son Bronx Mowgli and her career - and her marriage is suffering as a result, according to Us Weekly magazine.

A source tells the publication, "Ashlee is a loving mother, but she is overwhelmed."

The couple has been dogged by allegations of a break-up for months, and Simpson-Wentz was forced to dismiss the reports in March, with a spokesperson insisting "Everything is fine in their world."

But the rumours refuse to go away and Simpson-Wentz is reportedly infuriating the Fall Out Boy rocker with her recent partying and drunken behaviour.

She hit the headlines last week after launching a verbal attack on Wentz's ex-girlfriend, actress Michelle Trachtenberg, at a Los Angeles bash on 1 June. She subsequently apologized for the outburst, claiming there was a "misunderstanding" and that the two women "remain on good terms".

Sources close to the couple allege the bust-up wasn't the first time Simpson-Wentz has unleashed her fury.

An insider says, "Ashlee is having major problems with Pete right now. They fight constantly. She is seriously considering leaving him. They have been arguing a lot recently. They're in different places (in their lives)."

However, a representative for the 24 year old is adamant their romance is still going strong.

The spokesperson tells the magazine, "Ashlee and Pete are in a stable, happy marriage. They love one another and love being a family."