Taiwan's President Lai Ching-te has arrived in Eswatini, days after his government said a trip had been cancelled due to China pressuring African countries to stop him flying over their territories.

His visit to Eswatini - Taiwan's only diplomatic ally in Africa - followed "days of careful arrangements by the diplomatic and national security teams", he said, without giving further details on how he reached the country.

China described the visit as a "stowaway-style escape farce". China views Taiwan as part of its territory and has no right to state-to-state relations with it.

Images showed Lai being welcomed by Eswatini Prime Minister Russell Dlamini as he walked past a guard of honour.

Taiwan's delegation also included Foreign Minister Lin Chia-lung and National Security Council Adviser Alex Huang, according to its presidential office.

Lai's visit this time was not announced in advance by either government.

The trip had originally been set for 22 to 26 April, to mark the 40th anniversary of Eswatini's King Mswati III's accession. It was suspended after Taiwan said Seychelles, Mauritius and Madagascar had unilaterally revoked flight permits for Lai's aircraft to cross airspace they manage, citing Chinese pressure.

On social media, Lai said: "Taiwan will never be deterred by external pressures. Our resolve & commitment are underpinned by the understanding that Taiwan will continue to engage with the world - no matter the challenges faced."

In another post, he praised Eswatini for "standing firm against various diplomatic and economic pressure, speaking out for Taiwan's international place through concrete actions".

"I hope this trip will contribute to even deeper friendship between Taiwan and Eswatini, thanks to closer economic, agricultural, cultural and educational links, as well as promote Taiwan's international co-operation," he said.

Lai's schedule in Eswatini includes bilateral talks with Eswatini's King Mswati III and signing an agreement on customs, according to Taiwan's presidential office.

Eswatini, formerly known as Swaziland, is one of just 12 small states that have diplomatic relations with Taiwan. Keeping these ties is a priority for the Taiwanese government.

China has for years pressured countries to end diplomatic relations with Taiwan.

After Lai's visit to Eswatini, Beijing's foreign ministry said he had become "an international laughing stock".

"No matter how the Democratic Progressive Party authorities collude with external forces or in what form they 'buy the loyalty of others', it is all a futile effort that cannot change the fact that Taiwan is part of China," the ministry said, referring to Lai's party.

Beijing also urged Eswatini "to see clearly the general trend of history" and not "pull chestnuts out of the fire for a handful of 'Taiwan independence' separatists".

On Friday, China scrapped tariffs for all African countries, except Eswatini.