Prime Minister Rishi Sunak says he'll take more more action "to protect the lives and livelihoods" of Britons during months of planned strikes by transport, health and postal workers.
The government has repeatedly said it could not afford inflation-linked wage rises that would drive prices even higher.
Sunak told lawmakers in Parliament on Wednesday that the government had been reasonable and "has accepted the recommendations of a independent pay body, giving pay rises in many cases higher than the private sector."
"But if the union leaders continue to be unreasonable then it is my duty to take action to protect the lives and livelihoods of the British public, and that is why ... since I became Prime Minister, I have been working for new tough laws to protect people from this disruption."
His spokesperson said Sunak was looking at further measures to tackle the strikes. Sunak's choice of words that he wanted to "protect the lives" of Britons suggested he might introduce steps to protect the health service.
Asked during a BBC interview if the government could ban strikes in emergency services, he said: "My priority is making sure that I keep people safe ... and I will do what is required to do that".
The government already has legislation in Parliament to ensure minimum service levels are maintained on the transport system during strikes, but there is little in those plans that would cover walkouts by health workers.
"The Prime Minister thinks it's right to look at further ways to curb the impact of this disruption we're seeing," the spokesperson told reporters. "We want to come forward with more detail shortly, but I'm not going to put a timescale on it."
The head of the Unite trade union said it would continue to fight for workers.
"We will not be intimidated by anti-trade union attacks. If they put more hurdles in our way, then we will jump over them. We are ready industrially and financially," General Secretary Sharon Graham said in a statement.
Sunak, in power for just over a month, faces a raft of problems, including what could prove to be a lengthy recession in the run-up to an election that opinion polls suggest the Conservatives will lose.
Sir Keir Starmer, leader of the main opposition Labour Party, repeatedly accused Sunak of being weak, U-turning on earlier decisions because of pressure from his lawmakers.
"(This) shows the government is not serious right about avoiding these strikes," a spokesperson for Labour said.
"What we've been calling the government to do, consistently, is show the leadership that is needed to avert these strikes and avoid the disruption to the public."
Threat to Christmas travel
Border Force workers at several major British airports including the country's busiest, Heathrow, will go on strike for eight days this month in a dispute over pay, threatening disruption to Christmas travel.
The PCS trade union said staff employed by Britain's interior ministry in passport booths would take action at London's Heathrow and Gatwick airports and a handful of regional ones, plus the Port of Newhaven.
The union's General Secretary Mark Serwotka said around 2000 to 3000 staff would be involved in the walkouts on ever day but one between December 23-31.
Asked why the union had picked the Christmas period, Serwotka said: "Those people will lose pay when they go on strike, they do it as a last resort and the job of the union is to ensure that the action that we call is noticed."
Immigration minister Robert Jenrick said the decision was "unjustifiable" and would ruin the plans of thousands of families and businesses.
"While we are working closely with all UK ports and airports and have robust plans in place to minimise any delays if strike action goes ahead, passengers should be prepared for their plans to be severely disrupted."
Aviation analytics firm Cirium estimated more than 10,000 flights, potentially carrying more than 2 million people, were due to arrive at the affected airports between December 23 and 31.
Travellers in Britain already face major rail disruption over the Christmas period, with more than 40,000 railway workers due to walk out on December 13-14, 16-17, 24-27, January 3-4 and 6-7.
A Heathrow spokesperson said the airport was working with airlines and Border Force on plans to mitigate disruption.
Gatwick said it expected flights to operate as normal and it would also make extra airport staff available to help passengers on strike days.
