On Saturday, train delays of up to two hours occurred on the Rome-Naples and Rome-Florence lines, according to the state-owned Italian train company.
According to the company, the problems were caused by "unknown persons".
Matteo Salvini, one of the country's two deputy prime ministers and also Minister of Transport, wrote on X that "heinous criminal acts" are behind it.
"We have increased vigilance and expanded controls," he added.
At the start of the games on February 7, overhead wires for high-speed trains were cut near Bologna's central station, an important hub.
The authorities do not rule out that the suspected crimes may be politically motivated.
