Former sports minister Richard Caborn has said guidelines which stopped him taking his two grandchildren swimming are "totally disproportionate".
Mr Caborn said swimming pool managers were too risk-averse
The Sheffield Central MP said staff at the city's Graves Leisure Centre turned him away three times because he could not supervise the children one-on-one.
He said his grandchildren, aged four and five, were both able to swim.
Mr Caborn has urged the governing body, the Institute of Sport and Recreation Management (ISRM), to relax the rules.
He has asked the institute and Sheffield City Council to consider the use of a written disclaimer whereby a person would take full responsibility for those they are accompanying.
"It's getting crazy," said Mr Caborn.
"On the one hand they are trying to encourage children to swim but are getting totally risk-averse and tipping it the other way.
"I've written to the institute to see if they are supportive of a written disclaimer for grandparents and parents so they can take their children swimming.
"I've been stopped three times and both of them can swim. It's totally disproportionate for the risk entailed."
However, ISRM chief executive Ralph Riley said it was down to individual pools to implement their own policies.
He said: "There is not a hard and fast rule. It varies according to the attributes [of the swimmers].
"It is up to them [the pools] to provide services in what is a safe manner. It is their legal responsibility.
"We cannot impose it on them."