The RNLI has been criticised for not having lifeguards on beaches after two people died in separate incidents in Cornwall.
A 17-year-old girl trapped beneath a capsized boat and a man pulled from the sea died on Monday.
A councillor urged the lifeguard service to restart “as quickly as possible” to help save lives.
The RNLI said it had been put in an “impossible situation” and was doing what it could to restart its service.
But in an open letter, the charity’s chief executive Mark Dowie called on the government to restrict access to beaches “before more lives are lost”.
The deaths came after warnings about dangerous conditions over the bank holiday weekend.
The local girl who died was with three others who survived after their rigid inflatable boat capsized on the Doom Bar near Padstow, which is not an area that usually has lifeguard cover, at about 12:45 BST.
A man was pronounced dead after being pulled from the sea near Constantine by an off-duty RNLI lifeguard at about 12:25.
In a separate rescue, a man was pulled from the sea at Porthtowan by an off-duty RNLI lifeguard, and was taken to hospital in a serious condition.
Oliver Huntsman, from Bude Surf Lifesaving Club, said lifeguards were “a front-line service” and called for RNLI management to “pull their socks up”.
“Paramedics did not stop for eight weeks to figure out how they can keep their paramedics safe,” he said.
“[The RNLI] have had eight weeks of beaches being effectively closed to sort out a plan.”
Steve England, from surf magazine Carve, was surfing when he became involved in rescuing his friend at Porthtowan.
“Nobody understands why the RNLI won’t act,” he said.
“The ex-lifeguards are here, they daren’t leave the beach, they daren’t stop watching the water.”
Chris Lowry, from Porthtowan Surf Lifesaving Club, was also involved in that rescue and said lifeguards had been ready to intervene.
He said: “It is a testament to our lifeguards how keen they are to get involved, they can’t just sit idly by.”
Cornwall councillor Pete Mitchell said the authority contributed £1m a year to the RNLI for the lifeguard service.
“I can’t really get to grips about why they are standing off,” he said.
“I think they have really got to look at things very carefully and get back to the beaches as quickly as possible.”
The RNLI said it was “incredibly sorry” to hear about the incidents over the weekend and was doing all it could to get a lifeguard service up and running as soon as possible but “it must be safe for our lifeguards and the public when the risk posed by coronavirus is still a very real threat”.
In his letter, Mr Dowie said that restarting the service in a pandemic was not simple.
He wrote: “We’re asking for help to manage an impossible situation – we’re asking the public to heed our safety advice and we’re asking the government to restrict access to the coast until we have lifeguard patrols back on beaches.”