It was suggested to him, on the BBC's Andrew Marr Show, that the current action by junior doctors would be more effective if the ban was ended.
"Sympathy action is legal in most other countries, it should also be legal here," Mr Corbyn said.
The Tories said the remarks show Labour is a "threat" to economic security.
Asked if he would end the ban on secondary strike action - also known as solidarity action - brought in by Margaret Thatcher's Conservative government in 1990, Mr Corbyn said: "Yes, of course".
He added: "Nobody willingly goes on strike. They go on strike as an ultimate weapon... So let's look at the causes of people being upset rather than the symptoms."
Reaction to Sunday's political interviews
Mr Corbyn also did not rule out allowing the return of flying pickets - where workers travels to support others' action - which were first used in the coal disputes of the 1970s.
He said: "It was merely people moving around showing support during a very difficult industrial dispute."
Referring to the walkout by junior doctors in their dispute with the government about a new contract, Mr Corbyn said they "would be better served if we had a health secretary who was prepared to get involved, meet them and look for a solution".
There were calls for the laws on secondary strikes to be repealed in 2005 while Labour was in power, amid action by baggage handlers at Heathrow Airport in support of sacked staff at the catering firm Gate Gourmet. However, the government then ruled out the prospect of lifting the ban.
The issue re-emerged three years later but then Prime Minister Gordon Brown said there would be "no return" to past laws.

Sadie Hartley, 60, was stunned with a cattle prod and stabbed at her home in Helmshore, Lancashire, in January.
Preston Crown Court heard Sarah Williams, 35, exchanged naked photographs with Ms Hartley's partner Ian Johnston in the weeks prior to the death.
Ms Williams denies murder.
The court has heard Ms Williams was obsessed by Mr Johnston, 57, and "eliminated" Ms Hartley with the help of Katrina Walsh, 56,  who also denies murder, when he refused to leave her.
Mr Johnston, who had been in an "intermittent", "intimate" relationship with communications director Ms Hartley, began a sexual relationship with Ms Williams after they met in December 2012.
The former firefighter told Ms Williams the relationship was over months later, he said, but she kept contacting him in person or by text and even sent an anonymous letter to Ms Hartley, boasting the sender had had "fantastic" sex with Mr Johnston.
John McDermott, prosecuting, said Mr Johnston and Ms Williams exchanged naked photographs on 3, 4 and 5 December last year.
Mr Johnston said he didn't block the messages and responded "in kind" to Ms Williams' messages.
But he told the prosecutor he did not seek to rekindle the relationship and was "distraught" when he read the texts the next day.
There were further similar exchanges between the pair on Christmas Day, and again 10 days before the murder, Mr McDermott told the court.
Mr Johnston had been in Switzerland when the messages in January were sent, the court heard.
Mr McDermott asked: "What were your intentions with Sarah Williams once you would return to this country?"
Mr Johnston said: "Nothing at all. I can't recall half the text messages."
Ms Williams and riding instructor Katrina Walsh, 56, of Hare Lane, Chester, both deny murder.
Walsh is said to have played a key role in helping her friend to "eliminate" her love rival.
The trial continues.
A ban on sympathy strikes by unions not directly involved in a dispute would be repealed under a Labour government, the party's leader Jeremy Corbyn has said.
[NEXT_CONCEPT]
The partner of a woman killed with "demonic savagery" exchanged explicit texts and photos with the woman accused of her murder, a court has heard.