People are likely to swim on days when the beaches are not patrolled, which councillor Jenny Duncan said would potentially introduce significant risk to the community.
It would take an extra $29,000 from council to bring lifeguard wages up to the current minimum wage - $17.70 an hour.
But Surf Life Saving Wellington and Central Region has moved to a living wage for its lifeguards, Newell said, and Whanganui was under pressure to do the same.
Bringing lifeguard pay up to the $21.55 living wage next summer would cost an extra $45,000.
If council doesn't make that move Whanganui risks losing lifeguards to places with higher wages. About 80 per cent of lifeguards are university students, and many study in Wellington where lifeguard wages are higher.
Their service is non-profit, training they undertake is voluntary, Whanganui beaches are dangerous and lifeguards only get paid when they are on duty, Newell said.
Councillor Rob Vinsen asked him whether there were other sources of funding for the lifeguards. He said there were, but the service was already asking them for grants for equipment.
Councillor Helen Craig wanted to know whether there had been any progress on upgrading the surf club building at Castlecliff, and how that would be funded.
Planning for the upgrade is happening, Newell said, and the building is still safe to use. Funding has not been sought yet.
Councillors are to debate information from their 57 annual plan submissions on May 22-23, make any changes, and adopt the plan on June 27.