A General Social Care Council (GSCC) disciplinary committee suspended Maria Ward for two months and Gillie Christou for four months for their misconduct in the case.
But the panel ruled they could remain on the social care register, meaning they can resume working with vulnerable children by the autumn.
Peter Connelly was 17 months old when he died in a blood-spattered cot in Tottenham, north London, on August 3 2007.
He had suffered more than 50 injuries despite being on the at-risk register and receiving 60 visits from social workers, police and health professionals over eight months.
Ms Ward, 40, was Peter's nominated social worker at Haringey Council in north London from February 2007 until his death, and Ms Christou, 52, was her team manager.
GSCC disciplinary proceedings were brought against them this week, although they did not attend the London hearings.
The pair admitted failing to ensure Peter was visited regularly enough, not keeping adequate records and even losing contact with him for a time.
A GSCC conduct committee concluded it was a "serious case of misconduct" but not so grave that they should be struck off.
Panel chairman Jonathan Roberts said: "Not only did the committee consider that such a course was disproportionate to the facts admitted at this hearing, but if it did remove (them) it felt that it would only have been doing so to satisfy a perceived public demand for blame and punishment for a registrant who does not present a continuing risk. That would be wrong."
He said there was no evidence that either social worker had "deep-seated personality or attitudinal problems" or that they posed a significant risk of repeating the same behaviour.
The committee took into account the fact that Ms Ward and Ms Christou had already been suspended from social work for 16 months during the investigation.
Ms Christou was given a longer period of suspension because of her managerial role.
Mr Roberts highlighted mitigating factors including the two social workers' admissions of the allegations against them, their otherwise unblemished records and the staff shortages and excessive caseloads at Haringey Council at the time.
Trade union Unison, which supported Ms Ward and Ms Christou at the hearing, welcomed the committee's decision.
A Unison spokeswoman said: "It is right that the GSCC should recognise the challenging environment for social workers in Haringey.
"It is right to say that serious staff shortages, excessive caseloads, lack of managerial support and supervision have all played their part in making it difficult for social workers in the department to do their jobs.
"It is also right that the GSCC recognise that suspending these two
social workers from the register permanently would be a
disproportionate penalty, taken only to satisfy a perceived public demand for blame and punishment."
Haringey Council sacked Ms Ward and Ms Christou in April last year but they are challenging this through a tribunal.
Peter's mother, her boyfriend and his brother have been jailed over the death.