Tourism was Sri Lanka's third largest and fastest growing source of foreign currency last year (Reuters)

Sri Lanka will offer free tourism visas on arrival to citizens of almost 50 countries, a government document showed on Tuesday, as it tries to woo back visitors after terror attacks on Easter Sunday.

Terrorists on April 21 bombed churches and luxury hotels in Sri Lanka, killing more than 250 people, including 42 foreign nationals.

Several countries then issued travel advisories, undermining the crucial tourism industry. Foreign visitor arrivals in May fell 70.8 percent, the lowest since the end of Sri Lanka's civil war a decade ago.

A government document seen by Reuters showed the cabinet had agreed to scrap tourist visas, which typically cost $20 to $40 and are applied for online or at Sri Lankan embassies and consulates. Visa-free entry will be available to 48 nations, including China, India, and the United Kingdom.

"The offer will remain for six months and the government will assess the loss of revenue from visas after six months," an official at the Tourism Development Ministry told Reuters.

Tourism Development Minister John Amaratunga confirmed the measure to Reuters. He added that he expects the move to boost arrivals but declined to provide details. The ministry said it did not have an estimate of its earnings from visa payments.

Tourism was Sri Lanka's third largest and fastest growing source of foreign currency last year, after private remittances and textile and garment exports, accounting for almost $4.4 billion or 4.9 percent of gross domestic product in 2018.

Tourist traffic for the first half of the year was down by 13.4 percent.

The government will officially announce the offer at 0430 GMT on Wednesday, the Tourism Development Ministry official added.

Nationals from Thailand, European Union nations, the United States, Australia, South Korea, Canada, Singapore, New Zealand, Malaysia, Switzerland, Cambodia, Denmark, Sweden, Norway, Finland, Iceland, and Russia are among the 48 nations included in the measure.