"Waking up to the news of the earthquakes overnight here in New Zealand - we're fine," he tweeted.
"Thankfully at first light it seems the shakes have spared us from serious widespread damage. My thoughts n prayers are with the people of NZ," he further tweeted.
A tsunami hit two hours after the earthquake.
The US Geological Survey said the quake hit just after midnight, around 95 km from Christchurch, BBC reported.
Officials who have warned the residents to head inland or for higher ground along the coast, said the first waves may not be the largest, with tsunami activity possible for several hours. A gauge at Kaikoura, 181 km north of Christchurch, measured a wave of two metres, according to Weatherwatch.co.nz.
Smaller waves are said to be arriving in Wellington and other areas, the website said.
Thousands of people have already evacuated their homes, Radio New Zealand reported.
Christchurch is still recovering from the 2011 earthquake that killed 185 people and destroyed the city centre. According to the Herald newspaper, the tremor was felt all the way to Wellington, where sirens sounded and people fled buildings into the streets, some of them crying.
On his second trip to the country, Sidharth loved Christchurch.
"It has nice, easy vibes and it's comparatively younger I feel. It is less populated, which again makes this place very attractive for people like us who come from India. Its secluded, scenic, relaxed nature makes it a complete destination for anybody," he said.