Federal Labor MPs have begun circulating an email critical of former prime minister Kevin Rudd, in a sign of continuing tension within the party.

The email, which was sent to Mr Rudd this morning and copied to some of his colleagues, accuses the former Labor leader of being "childish" and "disloyal".It was sent by a resident of Avalon Beach on Sydney's northern beaches and forwarded onto the ABC by one of Prime Minister Julia Gillard's parliamentary supporters. The MP who initially shared the email with the ABC is not the only one to have done so."Your determination to destabilise the Government and your refusal to unconditionally support Julia Gillard, your leader and our Prime Minister, are despicable," the emailer tells Mr Rudd."You delight in half smiles and non-committal responses.You really belong in the Liberal Party because you are being so helpful to Tony Abbott's campaign and you don't now really seem to stand for anything but Kevin.