Protests and demonstrations are expected after the country’s president Maithripala Sirisena last week sacked the cabinet, suspended parliament and replaced prime minister Ranil Wickremesinghe.
One person was killed as tensions mounted over the weekend, the BBC reports.
Sri Lankan parliament speaker, Karu Jayasuriya, told reportrtd on Monday: "We should settle this through parliament, but if we take it out to the streets, there will be a huge bloodbath."
Mark Field, minister for Asia and the Pacific, said: “I am concerned by ongoing political developments in Sri Lanka and am following this fast-moving situation closely. Once again, I call upon all parties to uphold the constitution and due political and legal process.
“I urge President Sirisena, in consultation with the speaker, to reconvene the parliament immediately in order to give the democratically elected representatives of the Sri Lankan people their voice at this time.
“The UK, as a friend of Sri Lanka, remains committed to working with international partners and alongside the Sri Lankan government and people to support democracy, human rights, and reconciliation.”
The Foreign and Commonwealth Office has updated its travel advice for Sri Lanka, advising visitors to avoid demonstrations and gatherings.
“On October 26, the president of Sri Lanka sought to dismiss the prime minister, leading to a period of political instability,” said the FCO.
“Protests are expected in central Colombo on October 30. You should exercise vigilance and avoid all demonstrations or large political gatherings. Monitor this travel advice for further updates.”